hello friends, this is a tutorial for the language ‘c’

8/14/2019 Hello Friends, This is a Tutorial for the Language C.

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C

Hello friends, this is a tutorial for the language C. This is sosimple to say that we are learning C language however learning

any programming language is as tough as moving in a desert

without any idea of the end point. I am not trying to make you

afraid but its true. There is no end of computers. Lets look at

the basics of any language.

Till now we have worked on the computers without having any

idea of the calculations within the computer. We dont knowwhat goes on in the computers when we click the mouse button

or press a key on the keyboard. This is the internal calculation

of the computer.

Here, you are learning a programming language C. Let me

first introduce you to the programming language.

Language : A language is any medium through which we cancommunicate. So, in terms of computers, we can say that we

are needed to communicate with a computer through a

language.

Programming : A programming is not so tough as we thinks

generally. A simple plan of movie with friends is also a

programming in general life. Let us have an example of movie

with friends program. We will need to follow these steps forthat purpose

1. Be ready to go.

2. Call friends to meet you at theatre at a particular time.

3. Schedule yourself so that you can be at a particular time

at the proposed theatre.

4. Go to the theatre and take tickets.

5. Watch movie.

6. Come back to home.


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Now, we can say that a program of movie is in those six

instructions that must be followed to complete the movie

program. In the similar manners, a computer program is

developed to accomplish the particular task.

Lets see an example of adding two numbers :

1. Take two numbers.

2. Add them.

3. Give the result.

Before going to the programming, I need to explain some other

basic concepts of the computer which are important to be

known by a programmer and these will make the programming

more easier to understand.


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Computer Architecture :

The computer is classified in three different parts :1. Hardware

2. Software

3. User

Hardware : The physical components of the computer are

called as hardware. Example Monitor, Mouse, Keyboard, CPU

(Central processing Unit) etc.Software : All of the visual (Imaginary) things are called as

software. In computers, the things thing are seen on the display

device (Monitor generally) are called as software. This also

includes the pointer of mouse and the first screen of system

check when you just power on the computer. Example Ms

Windows, Ms-Word, avast antivirus software etc.

User : Obviously, a computer cannot be completed without aoperator. We humans are also the part of a complete computer.

HARDWAREHardware again is divided into three distinct parts.

1. Input Devices.

2. Output Devices

3. CPU

Input Devices : Input devices are those devices that are used

to send any instruction or command to the CPU. Example

Keyboard, Mouse, Joystick, Lightpen, Scanner, Thumbwheel,

BCR ( Bar Code Reader) etc.

Output Devices : Output Devices are those devices that areused to fetch the information from the CPU and give some


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results to the user. Example - Monitor, Printer, Plotter,

Speakers, BCW (Bar Code Writer) etc.

CPU : CPU (Central Processing Unit) is the most important part

of the computer. It is also called as the brain of the computer.

Mainly the computer exists in the CPU. All of the work is in the

CPU only. All processes, storage, calculations are done by the

CPU only. All other devices are connected to the CPU and

processes the request through it.


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These arrows shows the flow of data as data flows from Input

DevicesCPUOutput Devices.

Example : Suppose we want to add two numbers 4 and 6.

Firstly, we will enter the question 4+6 through the keyboard. It

will be sent to the CPU to process. It will be summed up to give

10 within the CPU but we will see it on the screen of the

monitor when it will be sent to it by the CPU.

It can also be understood by the sugar mill example. When we

want to produce sugar, firstly, the sugar cane is sent to the mill

to process. After processing from the mill, we get the sugar as

the final result.

CPU : We will discuss it after the software as it is a long topic.


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SOFTWARE

As we have discussed earlier, software is the visual part of thecomputer which do not exists in the physical manners. It can

only be seen through a hardware.

Software is classified in many parts however four major parts

are discussed here.

1. System Software

2. Application Software

3. Utility Software4. Custom Software

System Software : The software which are necessary for a

computer to work are under system software. These software

provide an environment to the user to work. Without a system

software, no one can use the computer. They also manages thememory and processing power of the computer. Example Ms-

Windows, Ms-DOS (Microsoft Disk Operating System), UNIX,

LINUX.

Application Software :These software are useful to complete

the user needs. These software are not necessary for the

computer but they are required by users to complete the jobs

needed to be performed by them. Example Ms-Office (Word,Excel, Power Point, Access, Outlook), Photoshop, Corel Draw,

Pagemaker, Tally, Kundli etc.

Utility Software : The software that are required to manage

the computer are under the section of Utility Software. This

includes the Antivirus software also. Example Avast, AVG,

Norton, Mc-Afee etc.


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Custom Software : These software are made by any

programmer. These software are not marketed by any

company and are available with limited users only. These

software are developed according to the need of the user and

sold to them only. They are not available with any other users.

Example Bank Software, School Software etc.


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CPU (CENTRAL PROCESSING UNIT)

CPU is the most important part of the computer. Without a CPU,all of the hardware is waste because it is the only device which

processes, stores and manipulates the data.

CPU is divided into three different groups :

1. ALU (Arithmetic Logic Unit)

2. MU (Memory Unit)

3. CU (Control Unit)

ALU : ALU is used for all of the mathematical calculations of

the computer. All of the calculations are performed by the ALU

only.

MU : MU is the memory of the computer. All of the storage isdone in this only.

CU : This unit is used to control all of the activities that goes on

within the computer. It controls all of the flow of data as well as

all of the functions of the computer.

Memory Unit is further divided into three different groups :

1. Primary Memory2. Secondary Memory

Primary Memory : The memory that is necessary for a

computer to work is under this section. It includes RAM

(Random Access Memory) and ROM (Read Only Memory).

Secondary Memory : Secondary memory is not necessary for

a computer. It can also be removed from the computer and thecomputer will work. Example CD (Compact Disk), VCD (Video


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CP

U

Cache

Memory

Primary Memory

(RAM)

Secondary

Memory

Compact Disk), DVD (Digital Video Disk), HD/HDD (Hard Disk /

Hard Disk Drive), Pan Drive, Floppy, Memory Card etc.

RAM :

RAM is a primary memory used for temporary storage of the

files. This memory is a volatile memory i.e. it loses all of its

data when power is off. This memory is directly attached to the

CPU. Here we are assuming primary memory out of the CPU.

CPU is considered to have the processor, ALU, CU and itsinternal registers. We will see this in next section.

ROM :

ROM is a microchip which is programmed once in its lifetime

when it is manufactured by the companies itself. The ROM

performs these operations :

1. Checks whether all of the hardware devices are connectedto CPU or not.

2. Whether all of the hardware devices are connected to

their proper place or not.

3. Give the starting point to start the Operating System

(Windows / UNIX / LINUX).

HIERARCHY OF COMPUTER


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Cache Memory : Cache memory is a small memory that

contains the recently processed data in it. It is very fast due to

low memory space. It is used to boost up the performance ofthe computer.

The speed of the processor is much faster as compared to other

devices. It is 6 to 7 times faster than the speed of RAM. So,

there is enough time for CPU to be in idle state while RAM

fetches the data. The speed of cache is much faster, nearly

equal to the speed of processor hence it boosts the system.

Fetching of Data :

Whenever there is a need of having some data, CPU generates

a request to both cache memory and RAM. If data is found in

cache memory, it is taken from that else RAM is checked. If the

required data resides in RAM, it is fetched else the request of

q33333333333333q333333333333333335the data is sent from

RAM to secondary memory like Hard disk and the data id

fetched from it to RAM and then it is sent to the CPU.


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Introduction to C

C is a programming language for the beginning levelprogrammers. This is a functional oriented language i.e. all of

the programs are in form of functions. The term function will be

discussed in later chapters. In this tutorial, we will cover the

following things.

1. Basic C programming

2. Conditional statements

a. If statementb. Switch Statement

3. Jump statements

a. Go to statement

b. Break statement

c. Continue statement

4. Looping

a. While loop

b. Do...While loopc. For loop

5. Pointers

6. Arrays

a. Single dimensional array

b. Multi dimensional array

c. Pointer to array

7. Strings

a. In form of array of charactersb. In form of pointers

8. Functions

a. Call by Value

i.Without return, No parameters

ii.Without return, with Parameters

iii.With return, No parameters

iv.With return, with parameters

b. Call by Referencec. Recursion


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d. Array in functions

9. Structure / Union

a. Simple structures

b. Array of structures

c. Pointer to structures

All of the given topics are fundamentals of language C. After

this, a programmer may proceed to any language like C++,

Java, .NET etc. or he/she may chose to be in advanced

programming in C.

Before going to the programming I would like to give some

introduction of work of programming languages, their use etc.

Till now, we have worked on the computer without knowing the

internal calculations. Now, let us understand some good things.

There are two type of screens we can use; the system program

screen and a user screen. The system program screen contains

all of the programs which are needed to be combined to form a

complete program and a user screen will have the output

/outcome result from that program. When we write a program

in any language, it is needed to be processed by someone so

that a result can be obtained. The compiler is the software

which processes the program written in C. Here I am saying it

in C only. Interpreter is also a software which performs the

same operation as of compiler. Every language have its own

compiler/interpreter. Several languages like java contains both

of them. C contains the compiler only and named as Turbo.

The difference in both is as:

Suppose we have a program of four lines, the compiler reads

whole program at once and compiles it as a whole however an

Interpreter reads the program line by line. So the whole process

can be shown by the following diagram.


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Source

Program in C

language.

Program

Screen

Output of the

program.

Output/User

Screen

Memory :

When we talk about memory, the unit of measuring of thememory must be well known. As we know, the computer a

electronic machine. Generally we uses English language while

working on the computer but it is not so that computer have

the knowledge of English language. Actually, the computer is

known about only two letters: 0 and 1. Just like an electric wire,

it may either contain some power in it or no power, in the same

manners computer may have 0 or 1. The language of 0s and

1s is called as Binary Language. The question arises thathow we are able to work in English if computer is not known

about English????

Ans: let us assume two persons of two different countries with

different languages like English and Chinese. None of them is

known about any other language and they need to

communicate with each other. They can use a third person who

is known about both the languages. Through this third personthey can communicate.

Assume a fruit Apple. In English it is made up of five different

letters A,p,p,l and e. In Chinese it may be of a single letter

suppose (chiu). So to form a chiu of single letter of Chinese,we used five letters but both points to the same thing. Like this

computer also works. It have a dictionary of all letters we use in

English and their equivalent binary code.

Compiled by Compiler


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ASCII Codes :

ASCII (American standard code for information interchange) is a

standard made for the computer world. In this standard, a

particular ASCII number is given to every alphabet in English.

The binary code of any letter can be found by converting that

number to its equivalent binary number. This is acceptable by

every computer of the world. There are total 256 codes. Some

of them are written here.

Some of the binary codes are as follows:

Letter ASCII

Code

Binary

Code

Letter ASCII

Code

Binary

Code

A 65 01000001 a 97 0110000

1B 66 01000010 b 98 0110001

0C 67 01000011 c 99 0110001

1D 68 01000100 d 100 0110010

0E 69 01000101 e 101 0110010

1F 70 01000110 f 102 0110011

0G 71 01000111 g 103 0110011

1H 72 01001000 h 104 0110100

0I 73 01001001 i 105 0110100

1J 74 01001010 j 106 0110101

0K 75 01001011 k 107 0110101

1

L 76 01001100 l 108 01101100


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M 77 01001101 m 109 0110110

1N 78 01001110 n 110 0110111

0

O 79 01001111 o 111 01101111

P 80 01010000 p 112 0111000

0Q 81 01010001 q 113 0111000

1R 82 01010010 r 114 0111001

0

S 83 01010011 s 115 01110011T 84 01010100 t 116 0111010

0U 85 01010101 u 117 0111010

1V 86 01010110 v 118 0111011

0W 87 01010111 w 119 0111011

1X 88 01011000 x 120 0111100

0Y 89 01011001 y 121 0111100

1Z 90 01011010 z 122 0111101

0

0 48 00110000 1 49 001100012 50 00110010 3 51 0011001

14 52 00110100 5 53 0011010

16 54 00110110 7 55 0011011

18 56 00111000 9 57 0011100

1


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NOTE : All of the binary codes are in 8 digits. It is true for all of

the letters of English.

A single 0 or 1 is called as bit. Hence we can say that 8 bits are

combined to form a character/letter. The 8 bit combination is

called as a byte. So, a byte contains a character.

8 bits = 1 byte / 1 character210 bytes = 1024 bytes = 1 KB (Kilo Byte)

220 bytes = 1024 KB = 1 MB (Mega Byte)230 bytes = 1024 MB = 1 GB (Giga Byte)240 bytes = 1024 GB = 1 TB (Terra Byte)

So, we can estimate the memory by these units of

measurement.

Computer Languages :

There are four type of languages in computers.

1. Low level language / Machine Language : Binary

Language

2. Assembly Language : Assembly

Language3. High Level Language :

Programming C etc.

4. 4GL (4th generation language) : SQL etc.

The difficulty in understanding the language decreases from

top to bottom. The low level is most difficult. The assembly


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language is somewhat simple than binary. HLL is more easier

and 4GL are as simple as our normal writing language.

The programs written in HLL or 4GL are firstly translated to

Assembly Language and then it works on machine/computer. It

is translated from assembly language to LLL by assembler.

Hence the complete hierarchy is as follows.

Now, let us move to the basic programming part of C.

Assembl

er

Compiler/Interp

reterHLL4GLAssembl

y

Languag

e

Machine

Languag

e


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BASIC C PROGRAMMING

The most simplest program is written in C is :

Now, let us see all of the parts of the program.

#

Its a pre-processor used for including header files or defining.

Include

it is used to call the header files into the program. As all of thefunctions of C are defined in header files. Example : printf is a

function defined in stdio.h file. The operation that must be

performed by calling printf is described in stdio.h file. So if we

want to use printf in the program, stdio.h must be a part of the

program. Hence it is included in the program by include

statement.

These works like a bracket to keep the complete name for the

header file.

stdio

this is a header file in the library of C and contains many

functions like printf , scanf, getc, putc, gets, puts etc.

.h

#include

void main()

{

printf(Hello, welcome to C);

}


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Indicates that it is a header file.

void

void means for blank. This indicates that main will not return

anything. This will be described in functions chapter.

main

main is the main function. Whenever a compiler compiles the

program, only main function is compiled. A program without

main function is always incomplete. It can not be compiled.

()

These brackets contains the parameters that are passed to the

functions. Even this will be described in functions topic.

{}

These brackets forms a block indicating that all of the things

written between them are part of the statement just above {. In

this program, printf statement is in the block of main function.

NOTE : All of the statements needed to be compiled must be

within the block of main function.

printf

printf is the statement which shows some output on the user

screen. The things written within double quotes() are printed

as it is on the user screen except some cases.

;

Semicolon (;) indicates the end of the line. It is also called as

termination symbol.

GETTING OUTPUT :

To get the output of the program, we will first compile it bypressing key F9. Then compiler will compile the program. If the


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program is correct. Success will be shown else error will be

displayed.

Now, we will run the program by pressing Ctrl+F9. Now, the

program is finished running. If we want to see the output

screen, we will press Alt+F5.

Step 1: Compile F9

Step 2: Run Ctrl + F9

Step 3: See output Screen (If required) Alt + F5

NOTE :

Instead of writing void main() we can also write

void main(void) No error No warning

int main() No error 1 warning (Function should return

a value)

int main(void) No error 1 warning (Function should return

a value)

PROGRAM 2 :

#include

void main()

{

printf(\nHello, \n\nwelcome \t\tto C);

}

OUTPUT:

Hello,

Welcome to C


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There is a very little difference in the previous program and this

one. There is a \n and \t in printf statement. It means for the

next line and tab space respectively. They both are used within

double quotes only. When we use \n, the cursor goes to the

next line and \t gives tab space. We can use them any number

of times according to our need and format of writing. They help

us to adjust the things in the display.

Now, try the following program.

TOPIC 2: getch() and clrscr()

getch() and clrscr() are two functions defined in conio.h header

file. So, to use them, we will need to include a extra header file.

#include

#include

void main()

{

printf(\n\nName\t\t:\tHimanshu Verma);

printf(\nCourse\t\t:\tB.Tech.\n);

printf(Branch\t\t:\tComputer Science);

}


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This line will be below inclusion of stdio.h. getch() is the

function that holds the output screen till we press any key on

the keyboard. This stands for get character. The main

purpose of getch well be discussed later but here we will use it

to hold the screen. The benefit of it will be we will not need to

press alt+F5 to see the screen after running the program.

When we will run the program, the screen will be holding for

any key from keyboard. We will use getch at the end of the

main function.

clrscr() is a function which clears the screen every time. Have a

experiment : compile the program many times without using

the clrscr function. The output will be displayed as many times

as you have compiled the program. To prevent this, we will use

clrscr at the first line of the program (here program means for

the program within the main function).

NOTE :This is not an hard and fast rule to use the clrscr at first

and getch at the last of the program. We can use them in

between also as our convenience.

Now, our simplest program becomes

Now, when we will run the program, it will hold for any key.

Also, the screen will be cleared at every compilation.

#include

#include

void main()

{

clrscr()

printf(\nHello, Welcome to C.);

getch()

}


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VARIABLES / CONSTANTS :

A variable is a quantity that can change its value and a

constant is a quantity that have a fixed value. Example : If x is2 then y is 4 else y is 6. In this case, we can not say the value

of y because it is changing. Hence y is a variable. If we are able

to give the exact value, it becomes constant.

DATA TYPES :

There are many different data types in C. Data type means for

any variable that can store anything in it. A variable may

contain any type of value it may be an integer type, it can

store values in decimal form i.e. floating type or a character.

Depending upon the nature of the variable, we uses them in

our programs. Generally, there are three basic data types

namely :

1. int (can store integer type of values)

2. float (can store floating type values i.e. decimal values)

3. char (can store a character in it)

There are many other data types also like long, double etc. but

the basic data types are three only.

There is the table of data type, memory space and range:

Data Type Memory

(Bytes)

Range

unsigned

char

1 0 to 255

char 1 -128 to +127unsigned 2 0 to 65,535


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intshort int 2 -32,768 to +32,767

int 2 -32,768 to +32,767unsigned

long

4 0 to 4,294,967,295

long 4 -2,147,483,638 to +2,147,483,637float 4 3.4 * 10-38 to 3.4* 1038

double 8 1.7* 10-308 to 1.7* 10308

long double 10 3.4* 10-4932 to 3.4* 104932

The declaration of variables is done after starting the main

function. The declaration is done according to our need of

program. Let us understand this with the help of a short

example :

#include#include

void main()

{

int a,b,c;

clrscr();

a=10;

b=20;

c=a+b;

printf(\nThe sum of %d and %d is %d,a,b,c);

getch();

}

OUTPUT :

The sum of 10 and 20 is 30


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In this program, two constants a and b area added in a variable

c. The value of a and b are fixed as 10 and 20. Hence they are

constants. The value of c depends upon the value of a and b so

a variable. Total memory consumption by this program is

2*3=6 bytes. To print the value of a variable, printf includes

some special symbols such as %d for integers. The table is

given as :

Data Type Symbol to be used

Int %dFloat %f Char %cDouble %e

long int %ld

The symbols are used within the double quotes and the name

of the variables are given after the quotes after a separation by

comma (,). If we need to use more than one variables to

display, more number of % symbols can be used and the

variable names can be given in respective order.


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We can use more than one number of data types in a single

program if required. We can also reduce number of variables in

the program. Let us see this from the previous example itself :

Here, I have declared the value of a and b in declaration only. It

is a technique to short up the program. Now in printf

statement, I have used (a+b) instead of writing c. In fact, the cis not even required to show the sum of a and b thats why it is

#include

#include

void main()

{

int a=10, b=20;

clrscr();

printf(\n%d + %d = %d,a,b,(a+b));

getch();

}

OUTPUT :

10 + 20 = 30


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not even declared. If we write any calculation in printf

statement, the calculation is solved first and then its value is

given. There is one more advantage of removing the number of

variables, memory. The memory consumption is also less. Now,

after reducing the variable c, the total memory consumption of

the program is 2*2=4 bytes only.

TOPIC 3 : scanf () function

scanf() function is defined in the stdio.h file. This method is

useful when we want the user to give the value of the variable

at the run time. This is used when we need to change the value

of the variable with each compilation.

Assume that we have a variable a of integer type and we want

to scan the variable. Then the statement will be as follows :

scanf(%d,&a);

when this line comes for compilation, the screen waits for a

integer type value to enter. We then gives the value and pressenter key. The value given is then stored in a. The value must

be in the range of -32768 to +32767 as it is a integer.

Let us understand this with the help of an example :


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Here, the underlined numbers are entered through keyboard

and then enter is pressed. Note that in scanf statement, two

variables are scanned hence two values are required at the run

#include

#include

void main()

{

int a, b, c;

clrscr();

printf(Enter two integer values : );

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

c = a + b;

printf(\n%d + %d = %d,a,b,c);

getch();

}

OUTPUT :

Enter two integer values : 25 15

25 + 15 = 40


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time. These values stores in a and b respectively and the

program continues to run after that.

OPERATORS :

There are many different type of operators in C.

1. Arithmetic Operators

2. Relational Operators

3. Logical Operators

4. Bitwise Operators

Operator Name

= Assignment Operator+ Addition- Subtraction

* Multiplication/ Division% Modulo++ Increment-- Decrement

Arithmetic Operators

Operator Name

== Comparative Equal< Less Than


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Greater Than>= Greater than equals!= Not equals

Relational Operators

Operator Name

&& And operator|| Or operator! Not operator

Logical Operators

Operator Name

& Bitwise And| Bitwise Or> Bitwise Right Shift^ Bitwise XOR

Bitwise Operators

Now, lets have an program in which the roll number, marks in

4 subjects of a student will be asked and then there will be autocalculation of total and percentage for the student.

#include

#include

void main()

{

int RN, s1, s2, s3, s4, total;

float per;clrscr();

printf(\nEnter the roll number : );

scanf(%d,&RN);

printf(Enter the marks of four subjects : );

OUTPUT :

Enter the roll number : 20

Enter the marks of four subjects : 80 76 86 78

Roll Number : 20Subject 1 : 80

Subject 2 : 76

Subject 3 : 86

Subject 4 : 78


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total = s1+s2+s3+s4;

per = (float)total/4;

printf(\n\n\n\nRoll Number\t:\t%d,RN);

printf(\nSubject 1\t:\t%d\nSubject 2\t:\t%d, s1, s2);

printf(\nSubject 3\t:\t%d\nSubject 4\t:\t%d, s3, s4);

printf(\n\nTotal = %d\nPercentage = %f, total, per);

getch();

}

Percentage = 80.000000


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Now, as we can see that the percentage is displayed up to six

points of decimal. It is not required. So to limit the floating point

variables, we can use some extra things in printf statement.

Suppose if we want to limit the floating point variable to 2

decimal points then we can use %0.2f instead of using %f in

printf statement. This is also true for the numbers with more

than 6 decimal points. If we need the number up to 20 decimal

points, we can use %0.20f. Try this.

INCREMENTING / DECREMENTING PROGRAMS :

In these programs we will see how the values of a variable

increases or decreases or changes by some quantity.

A=5;

A++;

In this line A++, the variable A is incremented by 1 unit. Now,

the value of A will be 6. In the similar manner, -- can be used.

The second type is :

A = A op X;

In this form, op is any operator (+,-,*,/,%) and X is any value,

constant or variable. We will understand this by an example.

A=8;

A = A* 2;

Here, the value of A is multiplied by 2 and then stored in A

itself. So, the value of A after the second statement will be 16.

Instead of using this method, we can use another method

which is more easy to write.

A = A op X can be replaced by


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A op=X;

These both are same. A=A*2 can also be written as A*=2;

SWAPPING PROGRAM :

Swapping is a good concept in computer field. Swapping means

for the interchange of the values of two different variables. To

do so, we can adopt two methods : with use of third variable &

without using third variable.

= operator is used to swap the variable values. Let us

understand the assignment operator more deeply.

A=10;

B=20;

B=A;

So, what you guess the values of A and B after these lines ???

Ans : B=10 and A=10

If I use

A=B

At the place of B=A, then the answer will change. Then the

result will be

A=20 and B=20.

So, the conclusion is that by use of assignment operator, the

left side value is assigned to the right side. This is the only

reason that we always uses

A=10 not 10=A.

This property will be used to swap.


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// Swapping with use of third variable.

#include

#include

void main()

{

int a, b, temp;

clrscr();

printf(\nEnter two integers to swap : );


printf (\n\nBefore swapping,\na = %d\tb = %d, a, b);

temp = a;

a = b;

b = temp;

printf(\nAfter swapping,\na = %d\tb = %d, a, b);

getch();

}

OUTPUT :

Enter two integers to swap : 20 10

Before swapping,

a = 20 b = 10

After swapping,

a = 10 b = 20


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Here, the value 20 is first given to temp, then a is assigned the

value of b i.e. 10 and then at the end, the value of temp (10) is

given to b to complete swapping process.


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// Swapping without using third variable.

#include

#include

void main()

{

int a, b;

clrscr();

printf(\nEnter two integers to swap : );


printf (\n\nBefore swapping,\na = %d\tb = %d, a, b);

a = a + b;

b = a - b;

a = a - b;

printf(\nAfter swapping,\na = %d\tb = %d, a, b);

getch();

}

OUTPUT :

Enter two integers to swap : 20 10

Before swapping,

a = 20 b = 10

After swapping,

a = 10 b = 20


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CHARACTER PROGRAM :

When we are using characters in our program, it is a little

complex to handle than integers and floating numbers. There is

a game of ASCII codes in characters and helps in somewhat

difficult programs. The assignment in characters is also little

different.

char ch;

ch = H;

here ch will contain H in it. We can also write it as

char ch = H;


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instead of giving the character itself, we can also give the ASCII

code of any letter to the variable. The variable will

automatically fetch the corresponding character and take it.

char ch = H;

or

char ch = 72;

we can have an experimental program also in which we can see

the ASCII value or the character corresponding to any integer

value. Try this program :

OUTPUT :

78 N

43 +

Before swapping,

a = 20 b = 10After swapping,

a = 10 b = 20

printf( %d %c\n%d %c, a, a, ch, ch);

getch();

}

// ASCII game.

#include

#include

void main()

{

int a= 78;

char ch = +;

clrscr();


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So, by this program we can say that the 78 contains the

character N and + has an ASCII code as 43. By this method, we

can have the A code of any character or find the character at

any ASCII code.

hello friends, this is a tutorial for the language ‘c’

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