Scrieti program c++.........

#include <iostream>
using namespace std;
int main ()
{
int z, x, y;
cin>> x; cin>>z;
while (x>0)
{
cin>>y;
if (z<y-x)
{
cout<<x%10;
}
else
{
cout<<y%10;
}
}
x=y;
return 0;
}