模板类以这样的代码开头:template<class Type>

class看作是变量的类型名,该变量接受类型作为其值,把Type看作是该变量的名称;

将模板信息放在一个头文件中，建立stacktp.h

#ifndef STACKTP_H_
#define STACKTP_H_
// 建立模板

template<class Type>
class Stack
{
private:
    enum {MAX=10};
    Type items[MAX];
    int top;
public:
    Stack();
    bool isempty();
    bool isfull();
    bool push(const Type & item);
    bool pop(Type & item);
};

template<class Type>
Stack<Type>::Stack()
{
    top=10;
}
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

建立源文件stacktem.cpp;

#include<iostream>
#include<string>
#include<cctype>
#include"stacktp.h"

using namespace std;
int main()
{
    Stack<string> st;// 创建一个空的stack,和前面的模板联系起来
    char ch;
    string po;
    cout<<"Please enter A to add a purchase order.\n"
        <<"P to precess a PO,or Q to quit."<<endl;
    while(cin>>ch && toupper(ch)!='Q' )
    {
        while(cin.get()!='\n')
        {
            continue;
        }
        if(!isalpha(ch))
        {
            cout<<'\a';
            continue;
        }
        switch(ch)
        {
        case 'A':
        case 'a':cout<<"Enter a PO number to add:"<<endl;
            cin>>po;
            if(st.isfull())
            {
                cout<<"stack already full"<<endl;
            }
            else
            {
                st.push(po);
            }
            break;
        case 'P':
        case 'p':
            if(st.isempty())
            {
                cout<<"stack already empty"<<endl;
            }
            else
            {
                st.pop(po);
                cout<<"PO #"<<po<<" popped\n";
                break;
            }
        }
        cout<<"Please enter A to add a purchase order,\n"
            <<"P to process a PO,or Q to quit.\n";
    }
    cout<<"Bye!"<<endl;

        return 0;
}

调试代码