Statements in C

All the statements in C ends with a ";". The various statements in C are

1)      Declaration Statement

2)      Assignment Statement

3)      Output  Statement

4)      Input Statement

5)      Control Statement

6)      Loop Statement etc.

It is used to specify the data type of variables used in the program

Syntax:

Datatype Variable or variables separated by , ;

int b;

Here the variable b is int and it allots 2 bytes

int c,e;

Here the variables c and e are int and it allots 4 bytes

float n1,n2;

Here n1, and n2 are declared as float and hence allotted 4 bytes each

The assignment statement is used to assign a constant to a variable.

Syntax:

Constant;

or

Variable = Variable;

or

Expression;

Eg: (assigned to a constant)

Eg: (assigned to a variable)

Eg: (assigned to a expression)

The output statement displays the values and after printing the values it points on the same line.

Syntax:

printf("string format", variable or variables separated by ,);

Here the format means the data specification of the variable. Say, for example

 integer format

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

 Decimal %d

 Octal %o

 Hexadecimal %x

float format

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

Without exponent %f

With exponent %e

Char %c

printf("Hello World");

The output is Hello World 

printf("%d",x)

The output is the value of x 

printf("sum %d",s)

The output is sum value of s

The input statement is used to read(accept) constant at the variable at the time of program execution.

Syntax:

scanf("format", & variable or &variables separated by comma,);

scanf("%d",&n);

It asks for the value of n

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

run 20

40 (ie.a=20 and b=40) 

The control statement denotes the sequence of execution of the program. There are two types of control statements namely: conditional control statement and unconditional control statement.

(1)Conditional control statement:

Here, the control is transferred to any part of the program without checking for any condition.

1. --------------

2. goto end

3. -------------

4. end:

5. -------------

goto labelname

The control is transferred to the line where the label starts as shown above.

(2) Unconditional control statement:

Here, the condition is first checked and if it is true then the executes that particular part and if false, then another part is executed.

Eg:  if

     if else

     switch

Loop statements are mainly used in programs to do repeated calculations.

Eg: while

    do .while

    for

Syntax:

    while (conditions)

    {

       statements;

    }

Structure of a Program:

Documentation Section

(remarks- comments)

Link section

(to link with other programs)

Global declaration Section

(common declaration)

main()

{

Declaration statement;

Statement part;

}

Sub programs

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

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

Sample Program:

/* program to find area of a square*/

main()

{

}