Template instantiations

The template name is not a type and cannot be used to declare a variable or call a function. To create a type or a function, the template must be instantiated. Most of the time, the templates are instantiated implicitly when they are used. We will again start with the function templates.

Function templates

To use a function template to generate a function, we have to specify which types should be used for all template type parameters. We can just specify the types directly:

template <typename T>
T half(T x) { return x/2; }
int i = half<int>(5);

This instantiates the half function template with the int type. The type is explicitly specified; we could call the function with an argument of another...