FOR

#include <iostream>
using namespace std;
int main()
{
int i,c,x;
for(i=100;i<=999;i++)
{
x=i/10;
c=i%10;
if(i== x*x-c*c)
cout<<i<<“ „;}
return 0;
}

WHILE

#include <iostream>
using namespace std;

int main() {
int i,x,c;

i=100;
while(i<999)
{
x=i/10;
c=i%10;
if(i==x*x-c*c)
cout<<i<<“ „;
i++;
}
return 0;
}