factorial of a number in C++

#include  
#include  
void main() 
{ 
int i,f,n; 
f=1;  
cout <<"enter the number \n"; 
cin > > n; 
  for(i=1;i<=n;i++) 
  f=f*i; 
cout <<"Factorial of number is "<<f; 
getch(); 
  }