C programming language

Syllabus

Programming concept:

Fundamental of C and

Operator in C and

Function array string pointer

C programming is a general-purpose, procedural, imperative computer programming language developed in 1972 by Dennis M. Ritchie at the Bell Telephone Laboratories to develop the UNIX operating system. C is the most widely used computer language.

extension ".c";

A C program basically consists of the following parts −Preprocessor CommandsFunctionsVariablesStatements & ExpressionsComments

#include

int main() {/* my first program in C */printf(“hello \n");

return 0;}

Token in ca token is either a keyword, an identifier, a constant, a

string literal, or a symbol. For example, the following C statement consists of five tokens

SemicolonsComments

IdentifiersA C identifier is a name used to identify a variable, function, or any other user-defined item. An identifier starts with a letter A to Z, a to z, or an underscore '_' followed by zero or more letters, underscores, and digits (0 to 9)

C does not allow punctuation characters such as @, $, and % within identifiers

auto else long Switch

break enum register Typedef

case extern return Union

char float short Unsigned

const for signed Void

continue goto sizeof Volatile

default if Static While

do int Struct _Packed

Whitespace in CA line containing only whitespace, possibly with a comment, is known as a blank line, and a C compiler totally ignores it.

Data types in c

Basic Types

(a) integer types and (b) floating-point types.

Derived types

They include (a) Pointer types, (b) Array types, (c) Structure types, (d) Union types and (e) Function types.

Type Storage size Value range

char 1 byte -128 to 127 or 0 to 255

unsigned char 1 byte 0 to 255

signed char 1 byte -128 to 127

int 2 or 4 bytes -32,768 to 32,767

unsigned int 2 or 4 bytes 0 to 65,535

short 2 bytes -32,768 to 32,767

unsigned short 2 bytes

long 8 bytes

unsigned long 8 bytes

Type Storage size Value range

float 4 byte 1.2E-38 to 3.4E+38

double 8 byte 2.3E-308 to 1.7E+308

long double 10 byte 3.4E-4932 to 1.1E+4932

A variable is nothing but a name given to a storage area that our programs can manipulate. Each variable in C has a specific type, which determines the size and layout of the variable's memory;

The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. Upper and lowercase letters are distinct because C is case-sensitive.

Variable Definition in C

Int x

Defining ConstantsThere are two simple ways in C to define constants −Using #define preprocessor.Using const keyword

#define int age=25;Const int age = 30;

We have four different storage classes in a C program −autoregisterstaticExtern

auto storage class is the default storage class for all local variables.

The register storage class is used to define local variables that should be stored in a register instead of RAM

The static storage class instructs the compiler to keep a local variable in existence during the life-time of the program

The extern storage class is used to give a reference of a global variable that is visible to ALL the program files

Arithmetic OperatorsRelational OperatorsLogical OperatorsBitwise OperatorsAssignment OperatorsMisc Operators

Decision condition

If

If-else

Nested if

switch statement allows a variable to be tested for equality against a list of values.

Loop

A while loop in C programming repeatedly executes a target statement as long as a given condition is true.

while(condition) {

statement(s);}

/* while loop execution */while( a < 20 ) {

printf("value of a: %d\n", a);a++;

}

A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.

for ( init; condition; increment ) {statement(s);

}

A do...while loop is similar to a while loop, except the fact that it is guaranteed to execute at least one time.

The syntax of a do...while loop in C programming language is −

do {statement(s);

} while( condition );

/* do loop execution */do {

printf("value of a: %d\n", a);a = a + 1;

}while( a < 10);

Arrays a kind of data structure that can store a fixed-size sequential collection of elements of the same type

Int a[5];

Initialize a array

Int a[5]={4,6,7,4,7}

pointer in C language is a variable which stores the address of another variable.

int n = 30;int* p = &n; // Variable p of type pointer is pointing to the address of the variable n oftype integer.

The string can be defined as the one-dimensional array of characters terminated by a null ('\0'). The character array or the string is used to manipulate text such as word or sentences

There are two ways to declare a string in c language.

By char array

By string literal

char ch[6]={‘v', ‘i', 'v', ‘e', ‘k', '\0'};

char ch[]=“vivek";

The gets() function enables the user to enter some characters followed by the enter key

The puts() function is used to print the string

The fscanf() function is used to read set of characters from file

The fputc() function is used to write a single character into file. It outputs a character to a stream.

The fgetc() function returns a single character from the file. It gets a character from the stream. It returns EOF at the end of file.

The maximum combined length of the command-line arguments including the spaces between adjacent arguments is

a. 128 charactersb. 256 charactersc. 67 charactersd. It may vary from one operating system to another

In the following code, the P2 is Integer Pointer or Integer?

typedef int *ptr;ptr p1, p2;

a. Integerb. Integer pointerc. Error in declarationd. None of the above

Input/output function prototypes and macros are defined in which header file?

a. conio.hb. stdlib.hc. stdio.hd. dos.h

Which standard library function will you use to find the last occurance of a character in a string in C?

a. strnchar()b. strchar()c. strrchar()d. strrchr()

What do the following declaration signify?

char **argv;

a. argv is a pointer to pointer.b. argv is a pointer to a char pointer.c. argv is a function pointer.d. argv is a member of function pointer

Which of the following is not a valid variable name declaration?a) int _a3;b) int a_3;c) int 3_a;d) int _3a

All keywords in C are in ____________a) LowerCase lettersb) UpperCase lettersc) CamelCase lettersd) None of the mentioned

Which of the following is not a valid C variable name?a) int number;b) float rate;c) int variable_count;d) int $main