嵌套类的定义及使用

C++ 嵌套类

嵌套类的定义

queuetp.h

#ifndef PRO1_QUEUETP_H
#define PRO1_QUEUETP_H
#include <cstring>
template <class Item>
class QueueTP {
private:
    enum {Q_SIZE = 10};
    // Node is a nested definition
    class Node{
    public:
        Item item;
        Node *next;
        Node(const Item & i):item(i), next(0){}
    };
    Node * front;
    Node * rear;
    int items;
    const int qsize;
    QueueTP(const QueueTP & q):qsize(0){}
    QueueTP &operator=(const QueueTP & q){ return *this; }
public:
    QueueTP(int qs = Q_SIZE);
    ~QueueTP();
    bool isempty()const { return items == 0; }
    bool isfull()const { return items == qsize; }
    int queuecount()const { return items; }
    bool enqueue(const Item &item);
    bool dequeue(Item &item);
};
// QueueTP methods
template <class Item>
QueueTP<Item>::QueueTP(int qs):qsize(qs) {
    front = rear = 0;
    items = 0;
}
template <class Item>
QueueTP<Item>::~QueueTP() {
    Node *temp;
    while (front != 0) {
        temp = front;
        front = front->next;
        delete temp;
    }
}
// Add item to queue
template <class Item>
bool QueueTP<Item>::enqueue(const Item &item) {
    if (isfull())
        return false;
    Node * add = new Node(item);
    if(add == NULL)
        return false;
    items++;
    if(front == 0)
        front = add;
    else
        rear->next = add;
    rear = add;
    return true;
}
// Place front item into item variable and remove from queue
template <class Item>
bool QueueTP<Item>::dequeue(Item &item) {
    if (front == 0)
        return false;
    item = front->item;
    items--;
    Node *temp = front;
    front = front->next;
    delete temp;
    if (items == 0)
        rear = 0;
    return true;
}
#endif //PRO1_QUEUETP_H

queuetp.cpp

#include "queuetp.h"

嵌套类的使用

main.cpp

#include <iostream>
#include <string>
#include <cstring>
#include "module13_nesting/template_nesting/queuetp.h"
using namespace std;
// 嵌套类的使用
void useNestClass(){
    QueueTP<string> cs(5);
    string temp;
    while (!cs.isfull()) {
        cout << "Please enter your name. You will be served in the order of arrival.\n name: ";
        getline(cin, temp);
        cs.enqueue(temp);
    }
    cout << "The queue is full. Processing bedins!\n";
    while (!cs.isempty()) {
        cs.dequeue(temp);
        cout << "Now processing " << temp << "...\n";
    }
}
int main() {
    useNestClass();
    return 0;
}