// test_template.cpp   define and use a function template

// define a template 

template <class typ >             // user chooses a type for 'typ'
typ funct( typ x, typ y, typ z)   // the function takes 3 parameters
{
   typ a, b;
   a = x + y;                     // our template limits the users
   b = y - z;                     // choice for 'typ' to a type
   return a * a / b;              // that has +, -, *, and / defined
}

#include <iostream>               // 'typ' must also have operator << defined
using namespace std;

int main()
{
  int i = funct(3, 5, 7);              // integer for typ
  long int j = funct(3L, 5L, 7L);      // long  int for typ
  unsigned int k = funct(3U, 5U, 7U);  // unsigned int for typ
  float x = funct(3.1F, 5.2F, 7.3F);   // float for typ
  double y = funct(3.1, 5.2, 7.3);     // double for typ
  cout << i << " int, "
       << j << " long, "
       << k << " unsigned, "
       << x << " float, "
       << y << " double.\n";
  return 0;
} // end main

// output is
// -32 int, -32 long, 0 unsigned, -32.8047 float, -32.8048 double.
// note the very different answer for the unsigned type
// remember a small negative number becomes a very large positive number