program menu queue

#include<stdio.h>
#include<conio.h>
#define MAX 10

int queue[MAX],front=-1,rear=-1;
void insert_element();
void delete_element();
void display_queue();


int main()
{
  int option;
  clrscr();
  do
  {
   printf("\n\n");
   printf("+===================+ \n");
   printf("|    Menu Queue     | \n");
   printf("+===================+ \n");
   printf("1.Insert Queue \n");
   printf("2.Delete Queue \n");
   printf("3.Display Queue \n");
   printf("4.Exit \n");
   printf("Enter your choice:  \n");
   scanf("%d",&option);
  
   switch(option)
   {
     case 1: insert_element();
              break;
     case 2: delete_element();
             break;
     case 3: display_queue();
             break;
     case 4: return 0;
   
     default :
            printf("Salah Memasukkan Pilihan tuh . . ! \n");
   }

  }
  while(option!=4);
  return 0;
}

void insert_element()
{
  int num;
  printf("\n Enter the number to be inserted: ");
  scanf("%d",&num);
  if(front==0 && rear==MAX-1)
    printf("\n Queue OverFlow Occured");
  else if(front==-1&&rear==-1)
  {
      front=rear=0;
      queue[rear]=num;

  }
  else if(rear==MAX-1 && front!=0)
  {
    rear=0;
    queue[rear]=num;
  }
  else
  {
      rear++;
      queue[rear]=num;
  }
}

void delete_element()
{
  int element;
  if(front==-1)
  {
      printf("\n Underflow");
  }
  element=queue[front];
  if(front==rear)
     front=rear=-1;
  else
  {
    if(front==MAX-1)
      front=0;
    else
      front++;
       printf("\n The deleted element is: %d",element);
  }

}

void display_queue()
{
    int i;
    if(front==-1)
      printf("\n No elements to display");
    else
    {
      printf("\n The queue elements are:\n ");
      for(i=front;i<=rear;i++)
      {
          printf("\t %d",queue[i]);
      }
    }
}