#include <stdio.h>

#include <stdlib.h>

​

#define QUEUE_LENGTH 10

​

int enqueue(int *queue, int *front, int *rear)

{

  if (*rear == QUEUE_LENGTH - 1)

  {

    printf("Queue is full.\n");

  }

  else if (*rear == -1 && *front == -1)

  {

    *rear = 0;

    *front = 0;

    printf("Give a number: ");

    int num;

    scanf("%i", &num);

    queue[*rear] = num;

  }

  else

  {

    printf("Give a number: ");

    int num;

    scanf("%i", &num);

    queue[++(*rear)] = num;

  }

}

​

int dequeue(int *queue, int *front, int *rear)

{

  if (*front == -1 && *rear == -1)

  {

    printf("Queue is empty.\n");

  }

  else if (*front == *rear)

  {

    printf("Removing %i...\n", queue[*front]);

    queue[*front] = 0;

    *front = -1;

    *rear = -1;

  }

  else

  {

    printf("Removing %i...\n", queue[*front]);

    queue[(*front)++] = 0;

  }

}

​

int print_queue(int *queue)

{

  printf("[ ");

  for (int i = 0; i < QUEUE_LENGTH; i++)

  {

    printf("%i ", queue[i]);

  }

  printf("]\n");

}

​

int main()

{

​

  int queue[QUEUE_LENGTH] = {0};

  int front = -1;

  int rear = -1;

​

  while (1)

  {

    int choice;

    do

    {

      printf("\tENQUEUE (0)\n");

      printf("\tDEQUEUE (1)\n");

      printf("\tPRINT (2)\n");

      printf("\tEXIT (3)\n");

      printf("\tGive choice: ");

      scanf("%i", &choice);

    } while (choice < 0 || choice > 3);

​

    switch (choice)

    {

    case 0:

      enqueue(queue, &front, &rear);

      break;

​

    case 1:

      dequeue(queue, &front, &rear);

      break;

​

    case 2:

      print_queue(queue);

      break;

​

    default:

      exit(0);

    }

  }

}