## Q. C++ Program to Check Whether the Given Number Is Perfect Number or Not.

Here you will find an algorithm and program in C++ programming language to check whether the given number is perfect number or not. First let us understand what Perfect number means.

**Explanation : **Perfect number is a positive integer equal to the sum of its proper divisors.

**For Example : ** 6 is perfect number because sum of its proper divisor(1, 2, 3) is equal to 6.

## Perfect Number Algorithm

START Step 1 - Input the number. Step 2 - Find all divisors of the number except the number itself. Step 3 - If the sum of all divisors of the number is equal to the number, then return true. Else, return false. STOP

# C++ Program to Check Perfect Number

#include <iostream> using namespace std; int main(){ int num=28,i=1,sum=0; while(i<num){ if(num%i==0) sum=sum+i; i++; } if(sum==num) cout << i << " is a perfect number\n"; else cout << i << " is not a perfect number\n"; return 0; }

#### Output

28 is a perfect number.