C++ Template Syntax

• The key word template warns the reader that what is being declared or defined is a template function or a template class as opposed to an ordinary function or class.
  
  
• The angle brackets <> that enclose the formal parameter lists indicate the parameters the template function or class depends upon. They serve the same purpose as () to enclose a formal argument list for a function.
  
  
• The word class tells that the kind of parameter is a type.
  
  
• The T is a formal name for the type much the same as formal function argument names are part of the definition of a function. The symbol T is not a keyword. (We could have used template<class Fred> just as well, replacing T with Fred everywhere in the template definition.) Most C++ programmers use T as a matter of simplicity and style.
  
  
• To use a function template we merely call the function, passing appropriate arguments. In your code it looks just like a normal function call. C++ looks at the call and the function template and generates a template function using the appropriate types.
  
  
• To create an instance of a template class requires providing the type of the formal parameter. For example, if we have a template class called Stack, we would create an instance of Stack for floats by saying: Stack<float&bt; float_stack; Now float_stack is an instance of a Stack<float>.
  
  
• Member functions of a template class are function templates. The definition of a member functions must start with the template prefix, template<class T>. Member functions defined outside the class definition (external rather than inline) must have the class name followed by the parameter. Thus a member function of class Stack would be externally defined by Stack<T>::Member().
  
  
• Constructor and destructor definitions do not require the duplication of the <T> in their names. That is, a constructor for template class Stack would be designated by: Stack<T>::Stack().