To print cube of a number in C++

#include<iostream.h>
#include<conio.h>
float cube(int x);
void main()
{
clrscr();
int a,c;
cout<<"enter any no";
cin>>a;
c=cube(a);
cout<<c;
getch();
}
float cube(int x)
{
int r;
r=x*x*x;
return (r);
}