int add(int n1,int n2)
{
     return n1+n2;
}
int _tmain(int argc, _TCHAR* argv[])
{
     int x1=4;
     int x2=5;
     int num=add(x1,x2);
     cout << "x1 * x2 = " << num << "\n";
     return 0;
}