C++ templates: (1)、类模板

1、类模板定义（主模板）

template<typename T, typename C=list<T>, int MAX=10>
class Stack{
public:
    using value_type = T;
public: 
    Stack(const T& a):m_oContainer{move(a)}{
        cout << "Stack<T,list<T>>()" << endl;
    }
    ~Stack(){}

    void push(const T& item){
        m_oContainer.push_front(item);
    }
    
    void pop(){
        m_oContainer.pop_front();
    }

    const T& top(){
        return m_oContainer.front();
    }

    int size(){
        return m_oContainer.size();
    }
private:
    C m_oContainer;
};

2、模板特化（偏特化）

       可以理解为模板的一个特例，需要特殊处理的情况

template<>
class Stack<int, vector<int>>{
public: 
    Stack(const int& a):m_oContainer{move(a)}{
    }
    ~Stack(){}

    void push(const int& item){
        m_oContainer.push_back(item);
    }
    
    void pop(){
        m_oContainer.pop_back();
    }

    const int& top(){
        return m_oContainer.back();
    }

    int size(){
        return m_oContainer.size();
    }
private:
    vector<int> m_oContainer;
};

3、别名模板

template<typename T>
using ListStack = Stack<T, list<T>>;

4、成员类型的别名模板

template<typename T>
using ListStackValueType = Stack<T, list<T>>::value_type;

5、推导指引

     说明如何转化类模板构造函数的参数类型

Stack( char const*)->Stack<string>;

完整示例代码:

#include <iostream>
#include <vector>
#include <list>
#include <vector>
using namespace std;

template<typename T, typename C=list<T>, int MAX=10>
class Stack{
public:
    using value_type = T;
public: 
    Stack(const T& a):m_oContainer{move(a)}{
        cout << "Stack<T,list<T>>()" << endl;
    }
    ~Stack(){}

    void push(const T& item){
        m_oContainer.push_front(item);
    }
    
    void pop(){
        m_oContainer.pop_front();
    }

    const T& top(){
        return m_oContainer.front();
    }

    int size(){
        return m_oContainer.size();
    }
private:
    C m_oContainer;
};

Stack( char const*)->Stack<string>;


template<>
class Stack<int, vector<int>>{
public: 
    Stack(const int& a):m_oContainer{move(a)}{
    }
    ~Stack(){}

    void push(const int& item){
        m_oContainer.push_back(item);
    }
    
    void pop(){
        m_oContainer.pop_back();
    }

    const int& top(){
        return m_oContainer.back();
    }

    int size(){
        return m_oContainer.size();
    }
private:
    vector<int> m_oContainer;
};

template<typename T>
using ListStack = Stack<T, list<T>>;

template<typename T>
using ListStackValueType = Stack<T, list<T>>::value_type;

int main(){
    Stack a("hello");
    Stack b{"hello"};
    Stack c = {"hello"};

    Stack d = 12;

    ListStack e = 1;
    ListStackValueType<char> f;
    return 0;
}