Check Perfect Number using C program

/*C program to check nunber is perfect or not.*/

#include <stdio.h>

int main()
{
    int num, loop;
    int sum;

    printf("Enter an integer number: ");
    scanf("%d", &num);

    sum = 0;

    for (loop = 1; loop < num; loop++) {
        if (num % loop == 0)
            sum += loop;
    }

    if (sum == num)
        printf("%d is a perfect number.", num);
    else
        printf("%d is not a perfect number.", num);

    return 0;
}

Using User Define Function

/*C program to check nunber is perfect or not.*/

#include <stdio.h>

/*function to check perfect number or not*/
int isPerfect(int num)
{
    int loop, sum = 0;

    for (loop = 1; loop < num; loop++) {
        if (num % loop == 0)
            sum += loop;
    }

    if (sum == num)
        return 1; /*Perfect Number*/
    else
        return 0; /*Not Perfect Number*/
}

int main()
{
    int num, loop;
    int sum;

    printf("Enter an integer number: ");
    scanf("%d", &num);

    if (isPerfect(num))
        printf("%d is a perfect number.", num);
    else
        printf("%d is not a perfect number.", num);

    return 0;
}

Output:

    First Run:
    Enter an integer number: 6
    6 is a perfect number.

    Second Run:
    Enter an integer number: 496
    496 is a perfect number.

    Third Run:
    Enter an integer number: 695
    695 is not a perfect number.