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(" %d", i);
 }
return 0;
}

Output:

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:

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.