type_traits.h
#pragma once
namespace wr
{
struct false_type {
static constexpr bool value = false;
};
struct true_type {
static constexpr bool value = true;
};
template<class T>
struct is_int:false_type {
};
template<>
struct is_int<int>:true_type {//特化
};
//模板处理
template<class T>
struct remove_ref {
using type = T;
};
template<class T>
struct remove_ref<T &> {
using type = T;
};
template<class T>
struct remove_ref<T &&> {
using type = T;
};
template<class T>
struct remove_const {
using type = T;
};
template<class T>
struct remove_const<const T> {
using type = T;
};
template<class T>
struct is_int_handler:is_int<typename remove_ref<typename remove_const<T>::type>::type> {
};
//也可直接对于每个特化使用继承的方法
template<>
struct is_int<const int> :is_int<int> {};
template<>
struct is_int<int&> :is_int<int> {};
}
main.cpp
#include"type_traits.h"
int main() {
using namespace wr;
cout << is_int<float>::value << endl;
cout << is_int<int>::value << endl;
cout << is_int<int&>::value << endl;
cout << is_int_handler<int&>::value << endl;
cout << is_int_handler<const int>::value << endl;
//cout << is_int<int&>::value << endl;
}
