类模板 模板做为参数

class Crab 类声明中调用
Thing<int> s1;    //       将T 设为 int
Thing<double> s2; //       将T 设为 double
          
//***************************************************//

Crab<Stack> nebuba;   //Stack必须式模板类

 

 

 

 

//////////////////////////////////////////////////
//
// stacktp.h -- a stack template
//
/////////////////////////////////////////////////
#ifndef STACKTP_H_
#define STACKTP_H_
template <class Type>
class Stack
{
private:
    enum {MAX = 10};    // constant specific to class
    Type items[MAX];    // holds stack items
    int top;            // index for top stack item
public:
    Stack();
    bool isempty();
    bool isfull();
    bool push(const Type & item); // add item to stack
    bool pop(Type & item);        // pop top into item
};

template <class Type>
Stack<Type>::Stack()
{
    top = 0;
}

template <class Type>
bool Stack<Type>::isempty()
{
    return top == 0;
}

template <class Type>
bool Stack<Type>::isfull()
{
    return top == MAX;
}

template <class Type>
bool Stack<Type>::push(const Type & item)
{
    if (top < MAX)
    {
        items[top++] = item;
        return true;
    }
    else
        return false;
}

template <class Type>
bool Stack<Type>::pop(Type & item)
{
    if (top > 0)
    {
        item = items[--top];
        return true;
    }
    else
        return false;
}

#endif

 

////////////////////////////////////////////////////////////
//
//main.cpp
//
///////////////////////////////////////////////////////////
// tempparm.cpp -- templates as parameters
#include <iostream>
#include "stacktp.h"

template <template <typename T> class Thing>
class Crab
{
private:
    Thing<int> s1;
    Thing<double> s2;
public:
    Crab() {};
    // assumes the thing class has push() and pop() members
    bool push(int a, double x) { return s1.push(a) && s2.push(x); }
    bool pop(int & a, double & x){ return s1.pop(a) && s2.pop(x); }
};
   
int main()
{
    using std::cout;
    using std::cin;
    using std::endl;
    Crab<Stack> nebula;
// Stack must match template <typename T> class thing  
    int ni;
    double nb;
    cout << "Enter int double pairs, such as 4 3.5 (0 0 to end):\n";
    while (cin>> ni >> nb && ni > 0 && nb > 0)
    {
        if (!nebula.push(ni, nb))
            break;
    }
  
    while (nebula.pop(ni, nb))
           cout << ni << ", " << nb << endl;
    cout << "Done.\n";
  
    return 0;
}