C++関数テンプレートと半順序とオーバーロード ref: http://qiita.com/_EnumHack/items/cd904d383588ddb2189f

file0.cpp

template < typename  T >
T max(T a, T b) ;

file1.cpp

max(1,2); // T is int
max(1.0, 3.0); // T is double

file10.cpp

template < typename T >
void f(T) ;

f({1,2,3}); // error!

file11.cpp

template < typename L, typename R >
auto f(L&& a, R&& b)
{
    return a + b ;
}

file12.cpp

template < typename L, typename R >
decltype(auto) f(L&& a, R&& b)
{
    return a + b ;
}

file13.cpp

template < typename L, typename R >
decltype(auto) f(L&& a, R&& b)
{
    return (a + b) ;
}

file14.cpp

template < typename L, typename R >
auto f(L&& a, R&& b)->decltype(a + b)
{
    return a + b;
}

file15.cpp

template <typename T, std::enable_if_t<pred>*& =nullptr_t>
void f(T t){}

file16.cpp

template <typename T>
std::enable_if_t<pred,ReturnType> f(T t){}

file17.cpp

template <typename T>
void f(T t,std::enable_if_t<pred>*=nullptr){}

file18.cpp

#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <map>

template < typename Container >
auto my_find(Container& c, typename Container::key_type key)
    ->decltype((c.find(key)))
{
    std::cout << "member" << std::endl;
    return (c.find(key));
}
template < typename Container >
decltype(auto) my_find(Container& c, typename Container::value_type v)
{
    std::cout << "free" << std::endl;
    return (std::find(c.begin(),c.end(), v)) ;
}

int main(){
    std::vector<int> a{1,2,3};
    std::map<int,int> b;
    b[0] = 1;
    b[2] = 3;
    b[4] = 5;

    auto&& iter1 = my_find(a,2);    
    std::cout << ( iter1 == a.end() ? "not found" : "found" ) << std::endl;
    std::cout << std::endl;
    auto&& iter2 = my_find(b,2);
    std::cout << ( iter2 == b.end() ? "not found" : "found" ) << std::endl;

    return 0;
}

file2.cpp

double max(double a, double b);  // #1

int max(int a, int b); // #2

max(1.0, 2.0); // calls #1
max(1,2) // calls #2

file3.cpp

template < typename T >
T f(T a, T b)
{
    return a + b ;
}

template < >
int f<int>(int a, int b)
{
    return a * b ;
} 

file4.cpp

template < typename T >
T f(T a, T b)
{
    return a + b ;
}

template < >
int f<int>(int a, int b) = delete ;

file5.cpp

template < typename L, typename R >
void f(L lhs, R rhs) ;

template < typename L >
void f<L,int>(L lhs, int rhs) ; // Error ! 

template < >
void f<int,int>(int lhs, int rhs) ; // OK ! 

file6.cpp

template < typename T >
void f(T* p) ; // Tのポインタのみを引数に取る

file7.cpp

template < typename T >
void f( typename hoge<T>::type ){} // non-deduced contexts

file8.cpp

template< std::size_t N >
void foo( int(&)[2*N] ){} // error

template< std::size_t N >
void bar( int(&)[N] ){} // OK

file9.cpp

template < typename T >
void f( T = 0 ) ;

f() // error!