Difference between for loop and while loop in C. | NEB Board Exam Class 12

Major Difference

for loop	while loop
for (initialization; condition; increment/decrement) { statement(s); }	while (condition) { statement(s); }
Initialization and increment/decrement expressions are specified within the loop header	Initialization and increment/decrement need to be done manually
Typically used when you know the number of iterations in advance	Used when you don't know the number of iterations in advance
The loop control variable is scoped to the loop body and header	The loop control variable is scoped to the surrounding block
Can create infinite loops using for (;;)	Can create infinite loops using while (1) or while (true)

Example:

For Loop

#include <stdio.h>

int main() {
    int n, factorial = 1;

    printf("Enter a positive integer: ");
    scanf("%d", &n);

    for (int i = 1; i <= n; i++) {
        factorial *= i;
    }

    printf("Factorial of %d is %d\n", n, factorial);

    return 0;
}

While Loop

#include <stdio.h>

int main() {
    int n, sum = 0;

    printf("Enter a positive integer: ");
    scanf("%d", &n);

    while (n != 0) {
        sum += n % 10;
        n /= 10;
    }

    printf("Sum of digits of %d is %d\n", n, sum);

    return 0;
}