Write a c program to check whether a given number is a perfect number or not.

Source Code:

 /* Write a c program to check whether a given number is a perfect number or not. (Perfect number is a positive number which sum of all positive divisors excluding that number is equal to that number. For example 6 is perfect number since divisor of 6 are 1, 2 and 3.  Sum of its divisor is 1 + 2+ 3 = 6) */

#include <stdio.h>

int main()

{

int n,sum; /*n to store the number, sum - to store the sum of factors*/

printf("Enter a number: ");

scanf("%d",&n); /*Input the  number from the test case 6, 28 & 45 respectively */

int i;

sum=0;

for(i=1;i<n;i++)

{

  if(n%i==0)

    sum=sum+i;

}

if(sum==n)

    printf("YES");

    else

    printf("NO");

    return 0;

}

Output: