how to use template in c++ code example

Example 1: c++ template function

template <class T>
void swap(T & lhs, T & rhs)
{
 T tmp = lhs;
 lhs = rhs;
 rhs = tmp;
}

Example 2: templates of templates c++

namespace std {
  template<typename t> struct hash<MyClass<t>>
  {
  	size_t operator() (const MyClass<t>& c) const;
  }
}

// You can also do things like

template<template<typename t> class type> func_name<type<t>>();