使用数组实现队列的C++程序
队列是一种抽象数据结构,包含一系列元素。队列实现FIFO机制,即先入先出。换句话说,在队列中,最先添加的元素也是最先被删除的元素。
下面是一个使用数组实现队列的程序:
示例
#include <iostream> using namespace std; int queue[100], n = 100, front = - 1, rear = - 1; void Insert() { int val; if (rear == n - 1) cout<<"Queue Overflow"<<endl; else { if (front == - 1) front = 0; cout<<"Insert the element in queue : "<<endl; cin>>val; rear++; queue[rear] = val; } } void Delete() { if (front == - 1 || front > rear) { cout<<"Queue Underflow "; return ; } else { cout<<"Element deleted from queue is : "<< queue[front] <<endl; front++;; } } void Display() { if (front == - 1) cout<<"Queue is empty"<<endl; else { cout<<"Queue elements are : "; for (int i = front; i <= rear; i++) cout<<queue[i]<<" "; cout<<endl; } } int main() { int ch; cout<<"1) Insert element to queue"<<endl; cout<<"2) Delete element from queue"<<endl; cout<<"3) Display all the elements of queue"<<endl; cout<<"4) Exit"<<endl; do { cout<<"Enter your choice : "<<endl; cin>>ch; switch (ch) { case 1: Insert(); break; case 2: Delete(); break; case 3: Display(); break; case 4: cout<<"Exit"<<endl; break; default: cout<<"Invalid choice"<<endl; } } while(ch!=4); return 0; }
上述程序的输出如下:
1) Insert element to queue 2) Delete element from queue 3) Display all the elements of queue 4) Exit Enter your choice : 1 Insert the element in queue : 4 Enter your choice : 1 Insert the element in queue : 3 Enter your choice : 1 Insert the element in queue : 5 Enter your choice : 2 Element deleted from queue is : 4 Enter your choice : 3 Queue elements are : 3 5 Enter your choice : 7 Invalid choice Enter your choice : 4 Exit
在上述程序中,函数Insert()将元素插入队列。如果rear等于n-1,则队列已满,显示溢出。如果front为-1,则将其加1。然后rear加1,并将元素插入到rear的索引中。如下所示:
void Insert() { int val; if (rear == n - 1) cout<<"Queue Overflow"<<endl; else { if (front == - 1) front = 0; cout<<"Insert the element in queue : "<<endl; cin>>val; rear++; queue[rear] = val; } }
在函数Delete()中,如果队列中没有元素,则为下溢条件。否则,显示front处的元素,并将front加1。如下所示:
void Delete() { if (front == - 1 || front > rear) { cout<<"Queue Underflow "; return ; } else { cout<<"Element deleted from queue is : "<< queue[front] <<endl; front++;; } }
在函数Display()中,如果front为-1,则队列为空。否则,使用for循环显示所有队列元素。如下所示:
void Display() { if (front == - 1) cout<<"Queue is empty"<<endl; else { cout<<"Queue elements are : "; for (int i = front; i <= rear; i++) cout<<queue[i]<<" "; cout<<endl; } }
函数main()向用户提供一个选择,询问他们是否要插入、删除或显示队列。根据用户的响应,使用switch调用相应的函数。如果用户输入无效响应,则打印该响应。此代码片段如下所示:
int main() { int ch; cout<<"1) Insert element to queue"<<endl; cout<<"2) Delete element from queue"<<endl; cout<<"3) Display all the elements of queue"<<endl; cout<<"4) Exit"<<endl; do { cout<<"Enter your choice : "<<endl; cin>>ch; switch (ch) { case 1: Insert(); break; case 2: Delete(); break; case 3: Display(); break; case 4: cout<<"Exit"<<endl; break; default: cout<<"Invalid choice"<<endl; } } while(ch!=4); return 0; }
广告
数据结构
网络
关系数据库管理系统 (RDBMS)
操作系统
Java
iOS
HTML
CSS
Android
Python
C语言编程
C++
C#
MongoDB
MySQL
Javascript
PHP