To check for perfect Number in C

By: Geek 🤓🤓 on 02:29

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Aim:

To write a ‘C’ program to find whether the given number is perfect number or not.

A number is a perfect number if the sum of the factors of the number other than itself is equal to that number.

Example: 28=1+2+4+7+14 is a perfect number.

Algorithm:

1. Read the number n.
2. If the number is less than 0 goto step  7
3. Initialize sum=0, i=1
4. if n % i=0 then sum=sum+i
5. Increment i. If i<n goto step 4
6. if sum=n
   Print the number is a perfect number
   else

Print the number is not a perfect number

7. Stop.

Program:

/* To find whether the given number is perfect number */

#include<stdio.h>

#include<conio.h>

void main()

{

int n,sum=0,i;

clrscr();

printf("Enter a number:");

scanf("%d",&n);

if(n>0)

{

for(i=1;i<n;i++)

if(n%i==0) sum=sum+i;

if(sum==n)

printf("\n\t%d is a perfect number",n);

else

printf("\n\t%d is not a perfect number",n);

}

else

printf("\n\tThe input number should be greater than zero");

getch();

}

Output -1:

Enter a number:28

       28 is a perfect number

Output-2:

Enter a number:56

       56 is not a perfect number

Output-3:

Enter a number:-28

       The input number should be greater than zero