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1 Basic concepts of queue
Features : The queue queueis a first-in-first-out ( FIFO, First In First Out) data structure, including two exits , inTailInsert element ( 入队), inLeader of the teamDelete element ( 出队).
Head of line/Head of line :, the front()queue container allows elements to be removed from the head of the line .
Endback() of the queue :, the queue container allows adding elements from the end of the queue .
Note: In the queue, onlyTeam headwithTailCan be accessed and used by the outside world, soQueue does not allow traversal behavior。
Join the team :, push()add elements to the end of the team.
Dequeue :, pop()remove elements from the head of the team/leader of the team.
2 queue common interface
Note: When using the queue container, you need to include the header file
#include <queue>.
Constructor :
① queue<T> que;: Default no-argument constructor, implemented by class template .
② queue(const queue &que);: Copy the constructor, use the existing queue object to initialize a new object.
Assignment operation ::
queue& operator=(const queue &que);Overload the assignment operator, use the target queue container to assign a value to the current queue container.
Data access ::
push(elem);Add elements to the end of the team.
pop();: Remove the element from the head of the team.
front();: Return to the first element of the team (the first element ).
back();: Return to the tail element (the last element ).
Size operation :
empty();Determine whether the queue is empty.
size();: Return the size/length of the queue.
Example : common interface for queue
#include <iostream>
using namespace std;
#include <queue>
class Person {
public:
string name;
int level;
Person(string name, int level) {
this->name = name;
this->level = level;
}
};
int main() {
//创建队列
queue<Person> q;
Person p1("唐僧", 30);
Person p2("孙悟空", 99);
Person p3("猪悟能", 60);
Person p4("沙悟净", 50);
//入队
q.push(p1);
q.push(p2);
q.push(p3);
q.push(p4);
cout << "当前队列大小：" << q.size() << endl; //4
//循环出队
while (!q.empty()) {
cout << "当前队首元素：" << q.front().name << endl;
cout << "当前队尾元素：" << q.back().name << endl;
cout << "***********" << endl;
//出队
q.pop();
}
cout << "当前队列大小：" << q.size() << endl; //0
return 0;
}