Looping

 Looping is used for repetition execution of same statement again & again

C are used to execute a block of code several times until the given condition is true. Whenever we need to execute some statements multiple times, we need to use a loop statement.

Types of looping

·         for loop

·         while loop

·         do while loop

For loop

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.

Syntax

The syntax of a for loop in C programming language is −

for ( init; condition; increment/ decrement  )

{

   statement(s);  // body of for loop

}

Here is the flow of control in a 'for' loop −

·      Where init=  This is  allows to initialize values for variable to start loop .

·      Wherecondition = is used to check the condition If it is condition is true, the body of the loop is executed until the given condition became false. If condition is false, the body of the for loop terminate  and the flow of  control jumps to the next statement just after the 'for' loop.

·      After the body of the 'for' loop executes, the flow of control jumps back up to the increment

/ decrement statement. This statement allows you to increase or decrease the value for variable initialized  at the begins  .

Note: for is also called entry loop

Flowchart  

Example c program that print the sum of natural number from 1 to 10

#include<stdio.h>

void main()

{

inti, sum=0;

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

{  

    sum=sum+i;

}

printf(“ sum of N natural num,ber from 1 to 10 is %d”, sum);

}

output

sum of N natural num,ber from 1 to 10 is  55

Example 2

#include <stdio.h>

int main () {

int a;

   /* for loop execution */

for( a = 1; a < 5; a++){

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

   }

   return 0;

}

Out put

value of a: 1
value of a: 2
value of a: 3
value of a: 4
value of a: 5

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