我的 DeQueue() 函数无法正常工作

Question

当我运行删除函数时，它给了我一些无限的垃圾值。有什么问题？

#include<iostream>
#include<process.h>
#include<conio.h>
using namespace std;
class circularqueue
{
  int arr[5];
  int front,rear;
  int size;
  int count;
  public:
     circularqueue()
     {
      count = -1;
      front=-1;
      rear=-1;
      size=5;
     }
     void display();
     void enqueue(int val);
     void delete_element();
     bool Is_empty();
};

bool circularqueue::Is_empty(){
    if(front == -1 && rear == -1){
        return true;
    }
    else {
        return false;
    }
 }
void circularqueue :: display()
{
    int F = front;
    for(count; count!=0;count--){
        cout<<"-----------"<<endl;
        cout<<"ID is : "<<arr[F]<<endl;
        cout<<"-----------"<<endl;
        F++;
        if(count == (size-1)){
            F=0;
        } 
        else if(count == -1){
            cout<<"Empty"<<endl;
        }
    }
}

void circularqueue :: enqueue(int val)
{
     if(Is_empty()){
     // cout<<"Queue is empty "<<endl;
        ++front;
        ++rear;
        arr[rear] = val;
     }
     else if(front == 0 and rear == (size-1)){
        cout<<"Queue is Full"<<endl;
     }
     else if(front==0 && rear == 0){
        if(rear<=(size-1)){
            arr[rear]= val;
            rear = rear+1;
        }
     }
     else if(front!=0 && rear == (size-1)){
        rear=0;
        arr[rear]=val;
        rear =rear+1;
     }
     else {
        arr[rear] = val;
        rear=rear+1;
     }
     count++;
}

当我运行此代码时，删除功能无法正常工作，请告诉我修复方法。

它给了我一些垃圾值，它看起来像一个无限循环

void  circularqueue :: delete_element()
{
    if(Is_empty()){
        cout<<"The Queue is empty"<<endl;
    }
    else if(front==(size-1)){
        front = 0;
    }
    else if(front == rear){
        front = -1;
        rear = -1;
    }
    else 
    {
        cout<<"Number Deleted : "<<front<<endl;
        front = front+1;
    }
    count--;
}
int main()
{
    circularqueue obj;

     int num;
     int ch;
     char ch1;
jb:  cout<<" 1 - EnQUEue   2- DeQueue  3- Display"<<endl;
     cin>>ch;
     switch(ch){
        case 1:{
            cout<<"Enter Number : "<<endl;
            cin>>num;
          obj.enqueue(num);
          cout<<"Return to Main Menu: "<<endl;
          cin>>ch1;
          if(ch1=='Y'|| ch1=='y'){
            system("cls");
            goto jb;
           }
            break;
         }
         case 2:{
            obj.delete_element();
             cout<<"Return to Main Menu: "<<endl;
          cin>>ch1;
          if(ch1=='Y'|| ch1=='y'){
            system("cls");
            goto jb;
           }

            break;
         }
         case 3:{
                obj.display();
                 cout<<"Return to Main Menu: "<<endl;
          cin>>ch1;
          if(ch1=='Y'|| ch1=='y'){
            system("cls");
            goto jb;
           }

            break;
         }
         default :{
            cout<<"Invalid entery  "<<endl;
             cout<<"Return to Main Menu: "<<endl;
          cin>>ch1;
          if(ch1=='Y'|| ch1=='y'){
            system("cls");
            goto jb;
           }
            break;
         }
     }
}

Answer 1

我已经为您的代码制作了一个更紧凑的版本，它执行相同的任务。看看这是否适合您。

#include<iostream>
using namespace std;

class CircularQueue{
    int arr[10], front, rear, size;
    const int max_size=sizeof(arr)/sizeof(int);
public:
    CircularQueue(){ front = rear = size = 0; }

    bool isEmpty(){ return front==rear; } // or simply size == 0

    bool isFull(){ return (rear+1)%max_size == front; } // or simply size == max_size - 1

    void enQueue(int val){
        if( isFull() ){
            cout << "Queue is Full" << endl;
            return;
        }
        arr[rear] = val;
        rear = (rear+1)%max_size;
        size++;
    }
    int deQueue(){
        if( isEmpty() ){
            cout << "Queue is Empty" << endl;
            return -1;
        }
        int ans = arr[front];
        front = (front+1)%max_size;
        size--;
        return ans;
    }

    void display(){
        if( isEmpty() ){
            cout << "nothing to display" << endl;
            return;
        }
        for( int i=0; i<size; i++ ){
            cout<<"-----------"<<endl;
            cout<<"ID is : "<<arr[(i+front)%max_size]<<endl;
            cout<<"-----------"<<endl;
        }
    }

};

int main(){
    CircularQueue ob;
    bool break_loop=false;
    while( !break_loop ){

        cout << "1 Enqueue, 2 Dequeue, 3 Display 4 Quit \nOption = ";
        int input; cin >> input;
        int tmp;
        switch(input){
            case 1 :
                cout << "Enter number " << endl;
                cin >> tmp;
                ob.enQueue(tmp);
                break;
            case 2 :
                tmp = ob.deQueue();
                if( tmp != -1 ) cout << "Element " << tmp << " deleted" <<endl;
                break;
            case 3 :
                ob.display();
                break;
            case 4 :
                break_loop = true;
                break;
            default :
                break;
        }
    }
    return 0;
}