TheDataStructuresSurvivalKit/Queue/Deque.cpp at main · DeepthiTabithaBennet/TheDataStructuresSurvivalKit · GitHub

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#include <iostream>
#include <stdio.h>

using namespace std;

#define size 5

int deque[size];
int f = -1;
int r = -1;
/*———————————————————————————————————————————————————————————————————————————*/
// enqueue_front function will insert the value from the front
void enqueue_front(int x){

    if((f == 0 && r == size - 1) || (f == r + 1)){
        cout << "Deque is full";
    }

    else if((f == -1) && (r == -1)){
        f = r = 0;
        deque[f] = x;
    }

    else if(f == 0){
        f = size - 1;
        deque[f] = x;
    }

    else{
        f--;
        deque[f] = x;
    }
}
/*———————————————————————————————————————————————————————————————————————————*/
// enqueue_rear function will insert the value from the rear
void enqueue_rear(int x){

    if((f == 0 && r == size - 1) || (f == r + 1)){
        cout << "Deque is full";
    }

    else if((f == -1) && (r == -1)){
        r = 0;
        deque[r] = x;
    }

    else if(r == size - 1){
        r = 0;
        deque[r] = x;
    }

    else{
        r++;
        deque[r] = x;
    }
}
/*———————————————————————————————————————————————————————————————————————————*/
// display function prints all the value of deque.
void display(){

    if((f == -1) && (r == -1)){
        cout << "Deque is empty";
    }

    else{
        int i = f;
        cout << "Elements in the Deque : ";

        while(i != r){
            cout << deque[i] << " ";
            i = (i + 1) % size;
        }
        cout << deque[r];
    }
    cout << endl;
}
/*———————————————————————————————————————————————————————————————————————————*/
// dequeue_front() function deletes the element from the front
void dequeue_front(){

    if((f == -1) && (r == -1)){
        cout << "Deque is empty";
    }

    else if(f == r){
        cout << "\nThe deleted element is " << deque[f];
        f = -1;
        r = -1;

    }

    else if(f == (size - 1)){
         cout << "\nThe deleted element is " << deque[f];
         f = 0;
     }

     else{
          cout << "\nThe deleted element is " << deque[f];
          f = f + 1;
     }
     cout << endl;
}
/*———————————————————————————————————————————————————————————————————————————*/
// dequeue_rear() function deletes the element from the rear
void dequeue_rear(){

    if((f == -1) && (r == -1)){
        cout << "Deque is empty";
    }

    else if(f == r){
        cout << "\nThe deleted element is " << deque[r];
        f = -1;
        r = -1;
    }

    else if(r == 0){
        cout << "\nThe deleted element is " << deque[r];
        r = size - 1;
    }

    else{
        cout << "\nThe deleted element is " << deque[r];
        r = r - 1;
    }
    cout << endl;
}
/*———————————————————————————————————————————————————————————————————————————*/
int main(){
    int code, num;

    do{
        cout << "Enter \n1 ————> EnQueue (front)\n2 ————> EnQueue (rear)\n3 ————> DeQueue (front)\n4 ————> DeQueue (rear)\n5 ————> Display\n6 ————> Exit\n";
        cout << "Please enter your choice : ";
        cin >> num;

        switch(num){
            case 1:
                cout << "\nEnter a Number : ";
                cin >> code;
                enqueue_front(code);
                break;

            case 2:
                cout << "\nEnter a Number : ";
                cin >> code;
                enqueue_rear(code);
                break;

            case 3:
                dequeue_front();
                break;

            case 4:
                dequeue_rear();
                break;

            case 5:
                cout << endl;
                display();
                break;

            case 6:
                break;

            default :
                cout << "Enter a number between 1 and 6\n";
        }
        cout << endl;
    }while(num != 6);

    return 0;
}