C program to check whether the input number is a perfect number or not using function.

Perfect Number: 

The Sum of all positive divisors except that number is equal to that number is known as the perfect number

 

Example: 

The smallest perfect number is 6.

Divisor of 6 are 1,2,3. The Sum of divisors is 1+2+3=6

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#include<stdio.h>

void per(int n)

{

     int i=1,s=0;

      while(i<n)

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     {

          if(n%i==0)

               s=s+i;

          i++;

     }

     if(s==n)

          printf("\nInput number is a Perfect Number:%d",i);

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     else

          printf("\n Input number is NOT a Perfect Number:%d",i);

}

int main()

{

     int num;

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     printf("Enter any Number : ");

     scanf("%d",&num);

     per(num);

     return 0;

}

Output:

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