## 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.
```