将顺序栈，循环队列定义成模板类型：

#include <iostream>

using namespace std;

template <typename T,int Maxsize>
class seqstack
{
private:
    T data[Maxsize];
    int top;
public:
    seqstack()      //无参构造
    {
        top=-1;
        cout<<"无参构造"<<endl;
    }

    seqstack(T d):data(d)       //有参构造
    {
        top==-1;
        cout<<"有参构造"<<endl;
    }

    bool isempty()  //判空
    {
        return top==-1;
    }

    int size()     //返回容纳的元素数
    {
        cout<<"栈中有"<<top+1<<"元素"<<endl;
        return top+1;
    }

    void push(T key)  //入栈
    {
        if(top==Maxsize-1)
        {
            cout<<"栈满"<<endl;
            return;
        }
        data[++top]=key;
        cout<<"入栈成功"<<endl;
        return;
    }

    void pop()  //出栈
    {
        if(top==-1)
        {
            cout<<"栈满"<<endl;
            return;
        }
        data[top--];
        cout<<"出栈成功"<<endl;
        return;
    }

};

template <typename T,int Maxsize>
class circularqueue
{
private:
    T data[Maxsize];
    int front;
    int rear;
public:
    circularqueue()      //无参构造
    {
        front=rear;
        cout<<"无参构造"<<endl;
    }

    circularqueue(T d):data(d)      //有参构造
    {
        front=rear;
        cout<<"有参构造"<<endl;
    }

    ~circularqueue()    //析构函数
    {
        cout<<"析构函数"<<endl;
    }

    int isfront()   //输出第一个元素
    {
        cout<<"队列中第一个元素为："<<data[front]<<endl;
        return data[front];
    }

    int isback()    //输出最后一个元素
    {
        cout<<"队列中最后一个元素为："<<data[rear-1]<<endl;
        return data[rear-1];
    }

    bool empty()    //判空
    {
        return front==rear;
    }

    int size()      //返回存储元素个数
    {
        cout<<"队列中存储了"<<(Maxsize-front+rear+1)%Maxsize<<"个元素"<<endl;
        return (Maxsize-front+rear+1)%Maxsize;
    }

    void push(T key)     //插入
    {
        if((rear+1)%Maxsize==front)
        {
            cout<<"队满"<<endl;
            return;
        }
        data[rear]=key;
        rear=(rear+1)%Maxsize;
        cout<<"插入成功"<<endl;
        return;
    }

    void pop()      //删除
    {
        if(front==rear)
        {
            cout<<"队空"<<endl;
            return;
        }
        front=(front+1)%Maxsize;
        cout<<"删除成功"<<endl;
        return;
    }
};

int main()
{
    seqstack<int,5> stack;
    if(stack.isempty())
    {
        cout<<"栈空"<<endl;
    }

    stack.push(1);
    stack.push(2);
    stack.size();
    cout<<endl;

    circularqueue<char,10> queue;
    if(queue.empty())
    {
        cout<<"队空"<<endl;
    }
    queue.push('a');
    queue.push('b');
    queue.size();
    queue.isback();
    queue.isfront();


    return 0;
}

思维导图：