The following code example is taken from the book
C++ Templates - The Complete Guide, 2nd Edition
by David Vandevoorde, Nicolai M. Josuttis, and Douglas Gregor,
Addison-Wesley, 2017
© Copyright David Vandevoorde, Nicolai M. Josuttis, Douglas Gregor 2017
#include "issame.hpp"
#include <iostream>
template<typename T>
void fooImpl(T, TrueType)
{
std::cout << "fooImpl(T,true) for int called\n";
}
template<typename T>
void fooImpl(T, FalseType)
{
std::cout << "fooImpl(T,false) for other type called\n";
}
template<typename T>
void foo(T t)
{
fooImpl(t, IsSameT<T,int>{}); // choose impl. depending on whether T is int
}
int main()
{
foo(42); // calls \TfooImpl(42, TrueType{})
foo(7.7); // calls \TfooImpl(42, FalseType{})
}