What is the difference between 'for' and 'while' loops

For loop: When it is desired to do initialization, condition check and increment/decrement in a single statement of an iterative loop, it is recommended to use 'for' loop.

Syntax:

for(initialization;condition;increment/decrement)

{

//block of statements

//increment or decrement

}

Program: Program to illustrate for loop

#include<stdio.h>

int main()

{

      int i;

      for (i = 1; i <= 5; i++)

           {

               //print the number

               printf("\n %d", i);

           }

               return 0;

}

Output:

12345

Explanation:

The loop repeats for 5 times and prints value of 'i' each time. 'i' increases by 1 for every cycle of loop. while loop: When it is not necessary to do initialization, condition check and increment/decrement in a single statement of an iterative loop, while loop could be used. In while loop statement, only condition statement is present.

Example:

#include<stdio.h>

int main()

{

     int i = 0, flag = 0;

     int a[10] = { 0, 1, 4, 6, 89, 54, 78, 25, 635, 500 };

    //This loop is repeated until the condition is false.

    while (flag == 0)

      {

             if (a[i] == 54)

                {

                      //as element is found, flag = 1,the loop terminates

                      flag = 1;

               }

                else

                     {

                                  i++;

                     }

       }

                printf("Element found at %d th location", i);

                            return 0;

}

Output:

Element found at 5th location

Explanation:

Here flag is initialized to zero. 'while' loop repeats until the value of flag is zero, increments i by 1. 'if' condition checks whether number 54 is found. If found, value of flag is set to 1 and 'while' loop terminates.