NPTEL (WEEK - 1)

Week - 1(Assinment -2 )

Write a program to find whether a given number (say x) is a “perfect number” or not.

Definition of Perfect number:

A perfect number is a positive integer that is equal to the sum of its proper positive divisors excluding the number itself. By this definition, 1 is not a perfect number.

Explanation:

Take number 6.

Proper positive divisors of 6 is 1,2,3 and their sum is 1+2+3=6.
So, 6 is a perfect number.

Constraint:
1<=x<=1,000,000

Input: A single positive number  x

Output:
yes if given number x is a perfect number

no if given number x is not a perfect number

#include<stdio.h> int main() { int f,sum=0,i; scanf("%d",&f); for(i=1;i<=(f/2);i++) { if(f%i==0) { // printf("%d",sum); sum+=i; } } if(sum==f) printf("yes"); else printf(("no")); return 0; }