What is a perfect number?
“Perfect number is a positive number which sum of all positive divisors excluding that number.”
For example 6 is Perfect Number since divisor of 6 are 1, 2 and 3. Sum of its divisor is
1 + 2+ 3 =6
and 28 is also a Perfect Number
since 1+ 2 + 4 + 7 + 14= 28
Other perfect numbers: 496, 8128
C++ Program
#include<iostream.h>
#include<conio.h>
void main() {
clrscr();
int i=1, u=1, sum=0;
while(i<=500) {
while(u<=500) {
if(u<i) {
if(i%u==0 )
sum=sum+u;
}
u++;
}
if(sum==i) {
cout<<i<<" is a perfect number."<<"\n";
}
i++;
u=1;
sum=0;
}
getch();
}
Output
6 is a perfect number. 28 is a perfect number. 496 is a perfect number.