Example: C Program to Check Armstrong Number without using pow() Function

// C Program to Check Armstrong Number without using pow() Function
#include <stdio.h>

int main() {
    int x, y, z, rem = 1, rem2 = 1, n = 0, m = 0;
    float r = 0.00;

    // x - To store the input number
    // y & z - To store the storage of original input number to check
    // rem & rem2 - To store the reminder values
    // r - To store the result variable

    printf("-----Enter the integer number-----\n");
    scanf("%d", &x);

    z = y = x;

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

    m = n;

    while (z != 0) {
        rem = z % 10;

        rem2 = 1;
        while (n > 0) {
        	rem2 *= rem;
        	--n;
        }
        n = m;

        r += rem2;
        z /= 10;
    }
    
    // if x is equal to r, the number is an Armstrong number
    if ((int) r == x) {
    	printf("%d is an Armstrong number.\n", x);
    } else {
    	printf("%d is not an Armstrong number.\n", x);
    }
    return 0;
}