Defining member function templates

So far, we have learned about function templates and class templates. It is possible to define member function templates too, both in non-template classes and class templates. In this section, we will learn how to do this. To understand the differences, let's start with the following example:

template <typename T>
class composition
{
public:
   T add(T const a, T const b)
   {
      return a + b;
   }
};

The composition class is a class template. It has a single member function called add that uses the type parameter T. This class can be used as follows:

composition<int> c;
c.add(41, 21);

We first need to instantiate an object of the composition class. Notice that we must explicitly specify the argument for the type parameter T because the compiler is not able to figure it out by itself (there is no context from which to infer it). When we invoke...