fundamentals of programmingc class1

8/6/2019 Fundamentals of ProgrammingC Class1

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C Programming

Class I


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Introduction to C

Generation of C Language1. In 1967, Martin Richards developed a language called BCPL

(Basic Combined Programming Language)

2. In 1970, Ken Thompson created a language using manyfeatures of BCPL and called it simply B.

3. In 1972, C is Introduced by Dennis Ritchie at Belllaboratories and in the UNIX operating system.


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TYPES OF C COMPILER

1. Borland C Compiler

2. Turbo C Compiler

3. Microsoft C Compiler

4. ANSI C Compiler

Why are using C It is a Structured Programming Language

High Level Language

Machine Independent Language It allows software developers to develop programs

without worrying about the hardware platforms wherethey will be implemented


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Steps in Learning C

Character set

Constants, variableAnd Data types

Control statements

Functions

Files

Structures andUnions

Pointers

Arrays

Data Structures

Algorithms

Programs


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CS Program StructureDocumentation section

Preprocessor section

Definition section

Global declaration section

main(){Declaration part;Executable part;

}

Sub program section{

Body of the subprogram}


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Cs Character set

C Character set

Source Characterset

ExecutionCharacter set

AlphabetsA to Z & a to z

Escape Sequences\a,\b,\t,\n

Digits0 to 9

Special Characters

+,-,,@,&,$,#,!


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C TOKENS

C TOKENS

Keywords

Identifiers

Strings

Special Symbols

Constants

Operators

-15.5

100

Grant_total

Amount

a1

float

while

ABC

YEAR

+ - * /

[ ]

{ }


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Cs keyword Basic Building Block of the Program

This are the Reserved words

This words cant be changed

C keywords

autobreakcase

charconstcontinuedefaultdo

doubleelseenum

externfloatforgotoif

intlongregister

returnshortsignedsizeofstatic

structswitchtypedef

unionunsignedvoidvolatilewhile


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Cs Variables

A variable is a data name as well as identifier that may beused to store a data value.

Rules for Naming the Variablesa) A variable can be of any combination of alphabets, digits and

underscore.

b) The first character of the variable cant be digits.

c) The length of the variable cant be exceeded by 8.(ANSI C 32Character)

d) No commas, blanks or special symbol are allowed within a

variable name.e) Uppercase and lowercase are significant. That is, the variable

Total is not the same as total or TOTAL.

f) It should not be a keyword.

g) White space is not allowed.


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Cs Variables cont.

Variable Declaration

It tells the computer what the variable name and type of the data

Syntax data_type a1,a2,a3..an;

Description data_type is the type of the data.a1,a2,a3an are the list of variables

Example int number;char alpha;

float price;


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Cs Variables cont.Initializing Variables

Initialization of variables can be done using assignment operator(=)

Syntax

a1 = c1 ;(or)

data_type a1 = c1;

Description a1 is the variablec1 is the constant

data_type is the type of the data

Example int a1 = 29;float f1 = 34.45;

char c1 = d


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Cs constant

C constant

Numeric constant

Character constant

Integer constanteg: roll_number = 12345;

Real constanteg: pi = 3.14;

Single Character constant

eg: ch = c; ch = 3;

String constant

eg: name = palani

The item whose values cant be changed during execution of program are called consta


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Cs constant Conti

Integer constanteg: roll_number = 12345;

Hexadecimal constantEg. 0x23

Octal constantEg. 043

Decimal ConstantEg. 35

Real Constanteg: pi = 3.14;

Double Precision ConstantSingle Precision Constant


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Data Types This are the type of the data that are going to access

within the program.

Cs Data Type

Primary User defined Derived Empty

Char

Int

Float

Double

typedef

Arrays

Pointers

Structures

Union

Void


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Cs Data types cont.

Integer

Signed

Unsigned

Int (%d)2 bytes,-32768 to 32767

Short int (%d)1 bytes, -128 to 127

Long int (%ld)4 bytes,

-2,147,483,648 to 2,147,483,647

Unsigned Int (%d)2 bytes, 0 TO 65, 535

Unsigned short int (%d)1 bytes, 0 TO 255

Unsigned Long int (%ld)4 bytes,

The primary data types are further classified as below.

Integers are the whole numbers, both positive and negative.


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Cs Data types cont.

Float Type

Float (%f )4 bytes, 3.4E -38 to 3.4E +38

Double (%lf)8 bytes, 1.7E -308 to 1.7E +308

Long Double (%lf)10 bytes, 3.4E -4932 to 1.1E+4932

Float are the numbers which contain fractional parts, bothPositive and Negative.


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Cs Data types cont.

Character Type

Char (%c)1 byte, -128 to 127

Signed Char (%c)

1 byte, -128 to 127

Unsigned Char (%c)1 byte, 0 to 255

Charare the characters which contain alpha-numeric character.Characters are usually stored in 8 bits (one byte) of internal storage

The void is the Null Data type.


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C Delimiters

Symbol Name Meaning

# Hash Pre-processor directive

, comma Variable delimiters (to separate list ofvariables)

: colon Label delimiters

; Semi colon Statement delimiters

() parenthesis Used in expressions or in functions

{} Curly braces Used in blocking C structure

[] Square braces Used along with arrays

Delimiters are the symbols, which has some syntactic meaning and hasgot significance.


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C Statements

Statements

Expression Statement Compound Statement Control Statement

Statement can be defined as set of declarations (or) sequence of actioAll statements in C ends with semicolon(;) except condition and

control statement


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Expression Statement

1. An Expression is a combination of constant, variables, operators, and function calls written inany form as per the syntax of the C language.

2. The values evaluated in these expressions can be stored in variables and used as a part forevaluating larger expressions.

3. They are evaluated using an assignment statement of the form.

variable = expression;

4. For Example,age = 21;

result = pow(2,2);

simple_interest = (p * n * r) / 100;

Algebraic Expression Equivalent C Expression

(mnp + qr at) (m*n* p+q*r-s*t)

(a+b+c) (x+y+z) (a+b+c)*(x+y+z)

abc / x+y (a*b*c) / (x+y)

8a3 + 3a2 + 2a 8*a*a*a+3*a*a+2*a

(a-b)+(x-y) / mn ((a-b)+(x-y)) / (m*n)

8.8(a+b-c) + c / pq 8.8 * (a+b-c) + (c / (p*q))


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CompoundStatements

1. A group of valid C expression statements placed within an opening flower brace {and closing flower brace } is referred as a CompoundStatements.2. For Example,

{X = (A + (B * 3) C);

Y = A + B * 3;Z = A * (B * 3 C);

}

1. This statement normally executed sequentially as they appear in the program.

2. In some situations where we may have to change the order of execution of statementsuntil some specified conditions are met.

3. The control statement alter the execution of statements depending upon the

conditions specified inside the parenthesis.4. For Example,

if (a == b) if ((x < y) && (y > z))

{ {

-------- -----------

-------- -----------

} }

Control Statements


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OperatorsAn operator is a symbol that specifies an operation to beperformed on the operands

Some operator needs two operands (binary)

Eg: a+b;

+ is an operator and a and b are the operands

Some operator needs one operand (unary)

Eg: ++a;

++ is an operator and a is the operand


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Types of Operatorsoperators

Arithmetic operator

Relational operators

Logical operator

Assignment operator

Increment and Decrement Operator (Unary Op.)

Conditional operator (Ternary operator)

Bitwise operator

Special operator


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Arithmetic Operators

Operator Meaning Examples

+ Addition 1+2 = 3

- Subtraction 3 -2 = 1

* Multiplication 2*2 = 4/ Division 2/2 = 1

% Modulo division 10/3= 1

This operators help us to carryout basic arithmetic operationssuch addition, subtraction, multiplication, division

Operation Result Examples

Int/int int 2/2 = 1

Real/int real 7.0/2 = 3.5

Int/real real 7/2.0 = 3.5

Real/real real 7.0/2.0 = 3.5


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Relational Operator This are used to compare two or more operands.

Operands can be variables, constants or expression.

eg: comparison of two marks or two values.

Operator Meaning Example Returnvalue

< is less than 5= is greater than or equal to 7>=5 0

== equal to 6==6 1

!= not equal to 5!=5 0


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Logical Operator

Operator Meaning Example Return value

&& Logical And (9>2) && (6>4) 1

|| Logical OR (9>2) || (3.4) 1

! Logical Not 4 ! 4 0

AND truth tableTrue True True

True False False

False True False

False False False

OR truth tableTrue True True

True False True

False True True

False False False

This operators are used to combine the results of two or moreconditions.


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Assignment Operator

This are used to assign a value or an expression or a variable to another variable eg: a = 10; n1 = 20;

Syntax:

identifier = expression;

a) Compound AssignmentThis operator are used to assign a value to a variable in order to assign a new

value to a variable after performing a specified operation.eg: a+=10,n1-=20;

b) Nested Assignment (Multiple)

This operator are used to assign a single value to multiple variableseg: a=b=c=d=e=10;


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List ofShorthand or Compound AssignmentOperator

Operator Meaning+= Assign Sum

-= Assign Difference

*= Assign Product

/= Assign Quotient

%= Assign Remainder

~= Assign Ones Complement

= Assign Right Shift

&= Assign Bitwise AND

!= Assign Bitwise OR

^= Assign Bitwise X - OR


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Increment and Decrement operator

C provide two operator for incrementing a value ordecrementing a value

a) ++ Increment operator (adds one to the variable)

b) -- Decrement operator (Minus one to the variable)

eg: a++ (if a= 10 then the output would be 11)

Operator Meaning

++X Pre increment

X++ Post increment

--X Pre decrement

X-- Post decrement


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Increment and Decrement operator Conti

Expression Result

+ + X 4

X + + 3

- - X 2

X - - 3

If the value of the operand x is 3 then the various expressions and their results

are

The pre increment operation (++X) increments x by 1 and then assign

the value to x. The post increment operation (X++) assigns the value to x andthen increments 1. The pre-decrement operation ( --X) decrements 1 and then

assigns to x. The post decrement operation (x--) assigns the value to x and

then decrements 1. These operators are usually very efficient, but causes

confusion ifyour try to use too many evaluations in a single statement.


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Conditional Operator

It is used check the condition and execute the statementdepending upon the condition

Syntax Condition?exp1:exp2

Description The ? operator act as ternaryoperator, it first evaluate thecondition, if it is true then exp1is evaluated if the condition is

false then exp2 is evaluatedExample a= 2; b=3

ans = a>b?a:b;

printf (ans);


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Bitwise Operator This are used to manipulate the data at bit level

It operates only on integers

Operator Meaning

& Bitwise AND

| Bitwise OR

^ Bitwise XOR

> Shift right

~ Ones complement


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Bitwise Operator cont.

Bitwise AND (both the operand

should be high for 1)

0 0 0

1 1 1

Bitwise XOR (the two operands

should be different for 1)

0 0 1

1 1 0

The truth table for Bitwise AND,OR and XOR

Bitwise OR (either of the operand

should be high for 1)

0 0 0

1 1 1

Eg: x = 3 = 0000 0011

y = 4 = 0000 0100

x&y = 0000 0000

Eg: x = 3 = 0000 0011

y = 4 = 0000 0100

x|y = 0000 0111

Eg: x = 3 = 0000 0011

y = 4 = 0000 0100

x ^ y = 0000 0111


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Bitwise Ones ComplementThe ones complement operator (~) is a unary operator, which causes the bits of the

operand to be inverted (i.e., ones becomes zeros and zeros become ones)

For Example, if x = 7

i.e 8 bit binary digit is 0 0 0 0 0 1 1 1

The Ones Complement is 1 1 1 1 1 0 0 0

Bitwise Left Shift Operator

The Left shift operator (


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Bitwise Right Shift OperatorThe Right shift operator (>>) shifts each bit of the operand to its Right. The general

form or the syntax of Right shift operator is

variable >> no. of bits positions

if x = 7 (i.e., 0 0 0 0 0 1 1 1) the value ofy in the expression

y = x >> 1 is 3

0 0 0 0 0 0 1 1 = 3 since it shifts the bit position to its right by one bit. The value stored

in x is divided by 2N (where n is the no of bit positions) to get the required value. For example, if x

= 7 the result of the expression y = x


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1. Each operator in C has a precedence associated with it.

2. This precedence is used to determine how an expression involving more than one operator isevaluated.

3. These are distinct levels of precedence and an operator may belong to one of these levels.4. The operators at the higher level of precedence are evaluated first.

5. The operators of the same precedence are evaluated either from left to right or from right toleft, depending on the level.

6. That is known as the associativity property of an operator.

What is Precedence Rule and Associative Rule


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Arithmetic operators precedence

The precedence of an operator gives the orderin whichoperators are applied in expressions: the highest precedence

operator is applied first, followed by the next highest, and so on.

eg: Arithmetic operator precedence

Precedence operator

High *,/,%

Low +,-

The arithmetic expression evaluation is carried out using twophases from left to right through the expressions


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Example:if (x == 10 +15 && y


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Precedence and Associativity Table

The following table lists all the operators, in order ofprecedence, with their associativity

Operators Operations Associativity priority

() Function call Left to Right 1

[] Square brackets

-> Structure operator

. Dot operator

+ Unary plus Right to Left 2

- Unary minus

++ Increment

-- Decrement

! Not


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Precedence and Associativity Tablecont.


~ Complement Right to Left 2

* Pointer operation

& Address operator

Sizeof Size of operator

type Type cast

* Multiplication Left to Right 3

/ Division

% Modulo

+ Addition Left to Right 4

- Subtraction


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> Right shift

< is less than is greater than

>= is greater than or equal to

== equal to

!= not equal to

& Bitwise AND Left to Right 7

| Bitwise OR

^ Bitwise XOR


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&& Logical And Left to Right 8

|| Logical OR

?= Conditional Right to Left 9=,*=,-=,&=,+=,^=,!=,=

Assignment Right to Left 10

, comma Left to Right 11


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Sample Expression

Exp = a - 2 * a * b + b / 4

Let us have a=10,b=20

exp = 10 - 2 * 10 * 20 + 20 / 4

Phase I exp = 2*10*20 , 20/4 will be evaluated.

phase II exp = 10-400+5 will be evaluated.

Result exp = -395.


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Expression Evaluation

Let us see some examples for evaluating expression.

Let a = 5, b = 8, c = 2.

x = b / c + a * c

410

14


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Let us see some examples for evaluating expression.

Let a = 5, b = 8, c = 2.

y = a + (b * 3) - c

29

27

24

Expression Evaluation


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TYPE CONVERSION

OR

TYPE CASTING


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What is Type Conversion or Type Casting

Type Casting means One data type converted into another data type. This is called Type

conversion or Type casting.

Example:

1. Integer into floating point number

2. Character into integer

3. Floating point number into Integer Number

Type conversion is classified into two types.

1. Implicit Type Conversion (Automatic Type Conversion)2. Explicit Type Conversion (Manual Type Conversion)

Type Conversion

Implicit

Conversion

Explicit

Conversion

Automatic

Conversion

Casting

Operation


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Type Conversion Hierarchy

short char

int

unsigned int

long int

unsigned long int

float

double

long double

Implicit

Type

Conversion

Explicit

Type

Conversion


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Implicit Type Conversion

1. The Implicit Type Conversion is known as Automatic Type Conversion.

2. C automatically converts any intermediate values to the proper type so that the expression can be

evaluated without loosing any significance.

3. Implicit type Conversion also known as Converted Lower order data type into Higher order data type.

4. Implicit Type Conversion also known asWidening.

Example:

int a, b;

float c;c = a + b;

Print c;

float a,b;

int c;

c = a + b; // This is Wrong

Print c;


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Explicit Type Conversion

1. The Explicit Type Conversion is, there are instances when we want to force a type conversion in a way

that is different from the automatic conversion.

2. The Explicit Type Conversion is Converted Higher order data type into Lower order data type.

3. The Explicit type Conversion is also known as borrowing.

4. The Explicit type conversion forces by a casting operator.

Disadvantage of Explicit Type Conversion

1. float to int causes truncation of the fractional part.

2. double to float causes rounding of digits.

3. Long int to int causes dropping of the excess higher order bits.

The general form of the casting is

(type_name) expression;

Where type_name is one of the standard C data type.

The expression may be a constant, variables or an expression.

For Example:

float a, b;

int c;

c = (int) a + (int) b;

Print c;


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Use of Casts

Example Action

x = (int) 7.5 7.5 is converted to integer by truncation.

a = (int) 21.3 / (int) 4.5 Evaluated as 21 / 4 and the result would be 5.

b = (double) sum / n Division is done in floating point mode.

y = (int) (a + b) The result of a + b is converted to integer.

z = (int) a + b a is converted to integer and then added to b.

p = cos ((double) x) Converts x to double before using it.


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Input And Output Functions


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Ip / Op Statements

We have two methods for providing data to the program.

a) Assigning the data to the variables in a program.

b) By using the input/output statements.

c language supports two types of Ip / Op statements

This operations are carried out through function calls.

Those function are collectively known as standard I / O library


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Ip / Op Statements cont.

Ip / Op Functions

Unformatted Ip / Op statementsInput Outputgetc() putc()getch() putch()Gets() puts()

Formatted Ip / Op statements

Input OutputScanf() printf()fscanf() fprintf()


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Unformatted Ip / Op statements

getch() function

Syntax char variable = getch();

Description

char is the datatype of the variable;

getch() is thefunction

Example char x = getch();

putch (x);

These statements are used to input / output a single / group of charactersfrom / to the input / output device.

Single character Input/output function

putch() function

Syntax putch (character variable);

Description char variable is the validc variable of the type ofchar data type.

Example char x ;

putch (x);


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cont.

gets() function

Syntax gets (char type of arrayvariable);

Descriptio

n

valid c variable declared

as one dimensional array.

Example char s[10];

gets (s);

Group of character Input / output function.

Gets() and puts are used to read / display the string from / tothe standard input / output device.

puts() function

Syntax puts (char type of arrayvariable)

Description valid c variable

declared as onedimensional array.

Example char s[10];

gets (s);

puts (s);


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cont.

getc() function

Syntax getc(char type ofvariable, file pointer);

Descriptio

n

The getc function returns

the next character fromthe input stream pointed

to by stream

Example int getc(FILE *stream );

Single character Input / output function with files.

Gets() and puts are used to read / display the string from / tothe standard input / output device.

putc() function

Syntax putc (char type ofvariable, file pointer)

Description The putc function

returns the character

written .

Example int putc(int c , FILE

*stream );

S l P


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Sample Program#include

Void main(){charname[10];charaddress[20];

Puts(Enter the name : );gets(name);puts(Enter the address : );gets(address);

puts(Name = )puts(name);puts(Address = );puts(address);

}



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Formatted Ip / Op statements It refers to Input / Output that has been arranged in a particular format.

Using this statements, the user must specify the type of data, that is

going to be accessed.

scanf() (This function is used to enterany combination ofinput).

Syntax scanf (control strings,var1,var2..var n);

Description control strings is the type of data that user going toaccess via the input statements.

var1,var2 are the variables in which the datas are

stored.

Example int n;

scanf (%d, &n);



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Formatted Ip / Op statements Control strings

i) It is the type of data that user is going to access via the input statement

ii) These can be formatted . iii) Always preceded with a % symbol.Formatcode

Variable type Display

%c Char Single character

%d Int Decimal integer -32768 to 32768

%s Array of char Print a Strings

%f Float or double Float point value without exponent

%ld Long int Long integer -65536 to 65535

%u Int Unsigned decimal integer

%e Float or double Float point values in exponent form

%h int Short integer


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Printf()

printf() (This function is used to display the result or the outputdata on to screen)

Syntax printf (control strings,var1,var2..var n);

Description Control strings can be anyone of the following

a) Format code character code

b) Execution character set

c) Character/strings to be displayed

Var1,var2 are the variables in which the datas arestored.

Example printf (this is computer fundamental class);

printf (\n Total is %d and average is %f,sum,avg);


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Control Statements(Decision Making)

Control Statements


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Control Statements

Control statements

Selection Statements Iteration statements

The if else statement

The switch statements

The while loop &Do while loop

The for loop

The break statement

Continue statement

Goto statement


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Types of Selection Statement

1. Simple if Selection statement2. if else Selection statement

3. Nested if else Selection statement

4. else if ladder Selection statement

Simple if Selection statement


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Simple ifSelection statement

It is used to control the flow of execution of the statements andalso to

test logically whether the condition is true or false.

if the condition is true then the statement following the if isexecuted if

it is false then the statement is skipped.

Syntax:

if ( condition )

{

statement ;

}

Test Condition

Executable X - Statement

True


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//Biggest of Two Numbers

#include

void main(){

int a, b;

clrscr();

printf(Enter the A and B Value:\n);scanf(%d, &a);

if (a > b)

{

printf(A is Big);

}

getch();

}



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It is used to execute some statements when the condition is true and execute some

other statements when the condition is false depending on the logical test.

Syntax:if ( condition )

{

statement 1 ; (if the condition is true this statement will be executed)}

else

{statement 2 ; (if the condition is false this statement will be executed)

}

Test Condition

Executable X - Statement

True

Executable Y - Statement

False


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// Biggest of Two Numbers

#include

void main()

{

int a, b;

clrscr();

printf(Enter the A and B Value:\n);

scanf(%d%d, &a,&b);

if (a > b)

{

printf(A is Big);

}

else

{

printf(B is Big);}

getch();

}

// Given Number is ODD or EVEN Number


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// Given Number is ODD or EVEN Number

#include

void main()

{ int n;

clrscr();

printf(Enter the Number:\n);

scanf(%d, &n);

if (n % 2 == 0)

{

printf(Given Number is Even Number);

}

else

{

printf(Given Number is Odd Number);}

getch();

}

N t d if l t t t


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Nested if.. else statement

Syntax:

if ( condition 1)

{

if ( condition 2)

statement 1 ;else

statement 2 ;

}

else

{

if (condition 3)statement 3;

else

statement 4;

}

when a series of ifelse statements are occurred in a program, we can write an entireifelse statement in another ifelse statement called nesting


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l if L dd M lti l if l St t t


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else if Ladder or Multiple if else Statements

Syntax:

if (condition_1)

executed statement_1;else if (condition_2)executed statement_2;

else if (condition_3)executed statement_3;

----------------------

----------------------else if (condition_n)

executed statement_n;else

executed statement_x;

When a series of decisions are involved we have to use more than one if elsestatement called as multiple ifs. Multiple if else statements are much faster than a

series of if else statements, since theif structure is exited when any one of the conditionis satisfied.


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Test Condition_1

Test Condition_2

Exec. Stat_1

Test Condition_3

TRUE

Test Condition_n

Exec. Stat_2

Exec. Stat_3

Exec. Stat_nExec. Stat_X

TRUE

TRUE

TRUE

FALSE

FALSE

FALSE

FALSE

else if Ladder


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else if Ladder

if (result >= 75)printf ( Passed: Grade A\n ) ;

else if (result >= 60)

printf ( Passed: Grade B\n ) ;

else if (result >= 45)printf ( Passed: Grade C\n ) ;

else

printf ( Failed\n ) ;

THE SWITCH STATEMENT


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THE SWITCH STATEMENT

The control statements which allow us to make a decision from the

number of choices is called switch (or) Switch-case statement. It is a multi way decision statement, it test the given variable (or)

expression against a list of case value.

switch (expression)

{ case constant 1:

simple statement (or)

compound statement;

case constant 2:


compound statement;

case constant 3:


compound statement;

}

switch (expression)

{ case constant 1:


compound statement;

case constant 2:


compound statement;

default :


compound statement;

}

Example Without Break Statement#include #include

Example With Break Statement


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#include

void main ()

{

int num1,num2,choice;

printf(Enter the Two Numbers:\n);

scanf(%d%d,&num1,&num2);

printf(1 ->A

ddition\n);printf(2->Subtraction\n);

printf(3->Multiplication\n);

printf(4->Division\n);

printf(Enter your Choice:\n);

scanf(%d,&choice);

switch(choice)

{

case 1:

Printf(Sum is %d\n, num1+num2);

case 2:

Printf(Diif. is %d\n, num1-num2);

case 3:

Printf(Product is %d\n, num1*num2);

case 4:

Printf(Division is %d\n, num1/num2);

default:

printf (Invalid Choice..\n);

}

getch();

}

#include

void main ()

{

int num1,num2,choice;

printf(Enter the Two Numbers:\n);

scanf(%d%d,&num1,&num2);

printf(1 ->A

ddition\n);printf(2->Subtraction\n);

printf(3->Multiplication\n);

printf(4->Division\n);

printf(Enter your Choice:\n);

scanf(%d,&choice);

switch(choice)

{

case 1:

printf(Sum is %d\n, num1+num2);

break;

case 2:

printf(Diif. is %d\n, num1-num2);

break;

case 3:

printf(Product is %d\n, num1*num2);

break;

case 4:

printf(Division is %d\n, num1/num2);break;

default:

printf (Invalid Choice..\n);

}

getch();

}

Rules for Switch


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Rules for Switch

The expression in the switch statement must be an integer or character constant.

No real numbers are used in an expression.

The default is optional and can be placed anywhere, but usually placed at end. The case keyword must be terminated with colon (:);

No two case constant are identical.

The values of switch expression is compared with case constant in the orderspecified i.e from top to bottom.

A switch may occur within another switch, but it is rarely done. Such statementsare called as nested switch statements.

The switch statement is very useful while writing menu driven programs.

Iteration Statements


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Iteration Statements1. Iteration statements is also known as Looping statement.2. A segment of the program that is executed repeatedly is called as a loop.

3.S

ome portion of the program has to be specified several number of times or until aparticular condition is satisfied.4. Such repetitive operation is done through a loop structure.5. The Three methods by which you can repeat a part of a program are,

1. while Loops

2. do.while loops3. for Loop

Loops generally consist of two parts :

Control expressions: One or more control expressions which control the execution of

the

loop,

Body : which is the statement or set of statements which is executed

over and

over


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Any looping statement , would include the following steps:

a) Initialization of a condition variableb) Test the control statement.

c) Executing the body of the loop depending on the condition.

d) Updating the condition variable.

While Loop


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e oop

A while loop has one control expression, and executes as longas that expression is true. The general syntax of a while loop is

A while loop is an entry controlled loop statement.

initialize loop counter;

while (condition)

{

statement (s);increment or decrement loop counter

}


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Start

Initialize

Test Condition

Body of Loop

Increment or Decrement

Stop

False

True

Example:


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p

// Print the I Values

#include

void main()

{

int i;

clrscr();

i = 0;while(i


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Start

Initialize

Test Condition

Body of Loop

Increment or Decrement

Stop

False

True


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Sl.No. while loop do-while loop

1. The while loop tests the condition before

each iteration.

The do whi le loop tests the condition after

the first iteration.

2. If the condition fails initially the loop is

Skipped entirely even in the first iteration.

Even if the condition fails initially the loop is

executed once.

Difference Between While Loop and Do While Loop

Example:


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// Print the I Values

#include

void main()

{

int i;

clrscr();

i = 1;while(i


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The for loop is another repetitive control structure, and is used toexecute set of instruction repeatedly until the condition becomesfalse.

To set up an initial condition and then modify some value to performeach succeeding loop as long as some condition is true.

The syntax of a for loop is

The three expressions :

expr1 - sets up the initial condition,

expr2 - tests whether another trip through the loop should be taken,

expr3 - increments or updates things after each trip.

for(expr1; expr2 ;expr3)

{

Body of the loop;

}


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Start

Initialize; test_condition; Increment / Decrement

Body of Loop

Stop

Example


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#include

void main()

{

for (int i = 1; i


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Case 1:

The statement

p = 1;

for (n = 0; n < 17; ++ n)

can be rewritten as

for (p = 1, n = 0; n < 17;++n)

Case 2:

The second feature is that the test condition mayhave any compound

relation and

the testing need not be limited only to the loop control variable.

sum = 0;

for (i = 1; i < 20 && sum < 100; ++ i)

{

sum = sum + i;

printf(%d %d\n, i, sum);

}

Additional Features of for Loop Conti


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Case 3:

It also permissible to use expressions in the assignment statements of initialization

and increments sections.

For Example:for (x = (m + n) / 2; x > 0; x = x / 2)

Case 4:

Another unique aspect of for loop is that one or more sections can be omitted, if

necessary.

For Example:

m = 5;for ( ; m ! = 100 ;)

{

printf(%d\n,m);

m = m + 5;

}

Both the initialization and increment sections are omitted in the for statement. The

initialization has been done before the for statement and the control variable is incrementedinside the loop. In such cases, the sections are left blank. However, the semicolonsseparating the sections must remain. If the test condition is not present, the for statementsets up an infinite loop. Such loops can be broken using break or goto statements in theloop.

Additional Features of for Loop Conti


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Case 5:

We can set up time delay loops using the null statement as follows:

for ( j = 1000; j > 0; j = j 1)

1. This is loop is executed 1000 times without producing any output; it simplycauses a

time delay.

2. Notice that the body of the loop contains only a semicolon, known as a nullstatement.

Nesting of for Loop


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g p

The One for statement within another for statement is called Nesting for Loop.

Syntax:

for (initialize; test_condi; incre. / decre.)

{

---------------

---------------for (initialize; test_condi; incre. / decre.)

{

-----------

-----------

}

---------------

---------------

}

-----------------

-----------------

Outer

for LoopInner for

Loop

Example

// Print the I and J Value


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// Print the I and J Value

#include#includevoid main(){

int I, j;clrscr();

for (i = 1; I < = 10 ; I ++){

printf (The I Value is %d \n", i);

for (j = 1; j < = 10; j ++){

printf (The J Value is %d \n",

j);}

}getch();}


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JUMPS IN LOOPS


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1. Loops perform a set of operations repeatedly until the control variable fails to satisfy the

test condition.2. The number of times a loop is repeated is decided in advance and the test condition is

written to achieve this.

3. Sometimes, when executing a loop it becomes desirable to skip a part of the loop or to

leave the loop as soon as a certain condition occurs.

4. Jumps out of a Loop is Classified into three types

1. break;

2. continue;

3. goto;


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The break Statement1. A break statement is used to terminate of to exit a for, switch, while or do while

statements and the execution continues following the break statement.

2. The general form of the break statement is

3. The break statement does not have any embedded expression or arguments.

4. The break statement is usually used at the end of each case and before the start of the next

case statement.

5. The break statement causes the control to transfer out of the entire switch statement.

break;

#include

void main()


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void main()

{

int i;

clrscr();

i = 1;

for(i=0;i


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The continue Statement The continue statement is used to transfer the control to the beginning of the loop, there

by terminating the current iteration of the loop and starting again from the next iteration

of the same loop.

The continue statement can be used within a while or a do while or a for loop.

The general form or the syntax of the continue statement is

The continue statement does not have any expressions or arguments.

Unlike break, the loop does not terminate when a continue statement is encountered, but it

terminates the current iteration of the loop by skipping the remaining part of the loop and

resumes the control tot the start of the loop for the next iteration.

continue;

#include

void main()


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void main()

{

int i;

clrscr();

i = 1;

for(i=0;i


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Sl.No. break continue

1. Used to terminate the loops or to exit loop

from a switch.

Used to transfer the control to the start of

loop.

2. The break statement when executed

causes

immediate termination of loop containing

it.

Continue statement when executed causes

Immediate termination of the current

iteration of the loop.

Differences Between Break and Continu

e Statement

The goto Statement


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The goto Statement The goto statement is used to transfer the control in a loop or a function from one point to

any other portion in that program.

If misused the goto statement can make a program impossible to understand.

The general form or the syntax of goto statement is

The goto statement is classified into two types

a. Unconditional goto

b. Conditional goto

goto label;

Statement (s);

.

label:

statement (s);

UnconditionalGoto


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The Unconditional goto means the control transfer from one block to

another block without checking the test condition.

Example:

#include

void main()

{

clrscr();

Start:

printf(Welcome\n);

goto Start;

getch();

}

ConditionalGoto

Th C diti l t th t l t f f bl k t th


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The Conditional goto means the control transfer from one block to another

block with checking the test condition.

#include

void main()

{

int a, b;

clrscr();

printf (Enter the Two Value:\n);

scanf (%d, &a, &b);

if (a > b)

goto output_1;

else

goto output_2;

output_1:printf (A is Biggest Number);

goto Stop;

output_2:

printf (B is Biggest Number);

goto Stop;

Stop:

getch();

}

STORAGE CLASSES


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STORAGE CLASSES

A storage class defines the scope(visibility) and life time of variables and/orfunctions within a C Program. There are

following storage classes which can beused in a C Program

* auto

* register

* static

* extern

auto - Storage Class


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auto Storage Class

auto is the default storage class for all

local variables.

auto int Month;

Example 1:

main()

{

auto int i=10;

printf(%d,i);}

Example 2:

main()

{

auto int i;

printf(%d,i);}

register - Storage Class


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register Storage Class

registeris used to define local variables that

should be stored in a register instead of RAM.

This means that the variable has a maximum

size equal to the register size (usually one word)and cant have the unary '&' operator applied to it

(as it does not have a memory location).

{

register int Miles;}

static - Storage Class


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static Storage Class

static is the default storage class for

global variables. The two variables below

(count and road) bothhave a static

storage class.static int Count;

E l


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Example

main()

{

add();

add();

}

add()

{

static int i=10;

printf(\n%d,i);i+=1;

}

E l


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Example

void func(void);

static count=10;

main()

{

while (count--)

{

func();}

}

void func( void )

{

static i = 5;

i++;printf("i is %d and count is %d\n", i, count);

}

extern - Storage Class


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g

All variables we have seen so farhave had limitedscope (the block in which they are declared) andlimited lifetimes (as for automatic variables).

However, in some applications it may be useful tohave data which is accessible from within any block

and/or which remains in existence for the entireexecution of the program. Such variables are calledglobal variables, and the C language providesstorage classes which can meet these requirements;namely, the external (extern) and static (static)classes.

Declaration for external variable is as follows:

extern int var;

E ample


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Example

int i=10;

main()

{

int i=2;

printf(%d,i);

display();

}

display()

{printf(\n%d,i);

}


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ThankYou!

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