C + + template meta-programming four: If statement runs at compile time

2.3If substitution

The IF statement is executed at compile time and can be implemented in a template-specific way. Here is the calling code:

Test ifcout << "test if" << endl;if<false>::run ();

The output is:

Test Ifit ' s false

The implementation of the template class is as follows:

Template<bool Condition>class If {public:  static inline void Run () {    cout << "It ' s true" << Endl ;  }}; Template<>class if<false> {public:  static inline void Run () {    cout << "It ' s false" << end l;  }};

C + + template meta-programming four: If statement runs at compile time