Template template parameters (C++ only)

Template template parameter declaration syntax

>>-template--<--template-parameter-list-->--class--+------------+--+------------------+-><
                                                   '-identifier-'  '-=--id-expression-'   

The following example demonstrates a declaration and use of a template template parameter:

template<template <class T> class X> class A { };
template<class T> class B { };

A<B> a;