• Source 
    1. #include<stdio.h>
    2. main() 
    3. {
    4. int num,n,i,sum=0;
    5. printf(" Please,Enter a number \(to check whether it is Perfect number or Not\) : ");
    6. scanf("%d",&num);
    7. n=num;
    8. for(i=1;i<=(n-1);i++)
    9. {
    10. if(n%i==0) 
    11. sum=sum+i;
    12. }
    13. if(sum==num)
    14. printf("\n %d is a perfect number.",num);
    15. else
    16. printf("\n %d is not a perfect number.",num);
    17.  
    18. }