模板函数与类模板

#include <iostream>#include <vector>using namespace std;int max_f(int a, int b){    std::cout << "int max_f(int a, int b)" << std::endl;    return a > b ? a : b;}template <typename T> T max_f(T a, T b){    std::cout << "template <typename T> T max_f(T a, T b)" << std::endl;    return a > b ? a : b;}//模板函数char*的特化template <> char* max_f(char* a, char* b){    std::cout << "template <> char* max_f(char* a, char* b)" << std::endl;    return strcmp(a,b) > 0 ? a : b;}template <typename RT, typename T1, typename T2> RT fun(T1 a, T2 b){    std::cout << "template <typename RT, typename T1, typename T2> RT fun(T1 a, T2 b)" << std::endl;    return a > b ? a : b;}//===============================================================================//非类型模板参数只能是整形或者指向外部链接对象的指针  http://blog.csdn.net/sophia_sy/article/details/1507077template <typename T = int, int szie = 10> //默认参数class A{public:    class subA{};    typename A::subA v1; //定义一个subA对象    subA subv; //定义一个subA对象    typedef typename A::subA sv1; //定义subA的类型    sv1 v; //定义一个sv1对象    template <typename T2>     A<T>& operator=(const T2& t2)    {        std::cout << "A<T>& operator=(const T2& t2)" << std::endl;        return *this;    }};template <char const* name>class B{public:    void f()    {        std::cout << name << std::endl;    }};//char const s[] = "hello"; //error，s是常量，不是变量，所以没有内部、外部链接属性extern char const s[] = "hello";int main(){    char* p = "a";    char* q = "b";    //非模板函数优先级高于模板函数 模板函数不支持类型的自动转换    max_f(3,5);     //int max_f(int a, int b)    max_f<>(3,5);   //template <typename T> T max_f(T a, T b)    由参数推导类型    max_f(3,5.2);   //int max_f(int a, int b)    max_f('a',5);   //int max_f(int a, int b)    max_f('a','b'); //template <typename T> T max_f(T a, T b)    max_f(p,q);     //template <> char* max_f(char* a, char* b)    max_f("a","abc"); //const char* //template <typename T> T max_f(T a, T b)    fun<float>(1,2); //fun<RT,T1,T2>, T1 T2 可以从参数表中推导    std::cout << "===========================================" << std::endl;    A<> a;   //使用模板A的默认参数类型    a = 1;   //template <typename T2> A<T>& operator=(const T2& t2)    std::cout << "===========================================" << std::endl;    B<s> b;    b.f(); //hello    system("pause");    return 0;}