Why do I get a Compilation error?

i have tested this code on my computer while using Turbo c++ . but this is not compiling in c++ 4.0.0-8.

#include<iostream.h>
#include<conio.h>
void main()
{
int x;
float y;
cin>>x;
cin>>y;
if(x%5==0){
y=(y-x)-0.50;
}
cout<<y;
getch();
}