Implements Queue in C language

C language is always very useful to implements data structure. This program will be highly helpful for the students and professional to use queue using C language.

#include <stdio.h>
#include<stdlib.h>
#define MAX 9
void push(int queue[],int *front,int *rear,int item)
{
 if((*front==0 && *rear==MAX) || (*rear+1==*front))
 {
  printf("\nOver Flow.....");
  return;
 }
 else if(*front==-1)
 {
  *front=0;
  *rear=0;
 }
 else if(*rear==MAX)
 {
  *rear=0;
 }
 else
 {
  *rear=*rear+1;
 }
 queue[*rear]=item;
}
int pop(int queue[],int *front,int *rear)
{
 int a;
 if(*front==-1)
 {
  printf("\nUnder flow......");
  return -1;
 }
 else
 {
 a=queue[*front];
 if(*front==MAX)
 {
  *front=0;
 }
 else if(*front==*rear)
 {
  *front=-1;
  *rear=-1;
 }
 else
 {
  *front=*front+1;
 }
 return a;
 }
}
void display(int queue[],int front,int rear)
{
 int i;
 if(front<=rear)
 {
  for(i=front;i<=rear;i++)
  {
   printf("\nPosition: %d\tVaue: %d",i,queue[i]);
  }
 }
 else
 {
  for(i=0;i<=rear;i++)
  {
   printf("\nPosition: %d\tVaue: %d",i,queue[i]);
  }
  for(i=front;i<=MAX;i++)
  {
   printf("\nPosition: %d\tVaue: %d",i,queue[i]);
  }
 }
}
int menu()
{
 int c;
 printf("\n1.Insert\n2.Delete\n3.Display\n4.Exit");
 printf("\nEnter your choice: ");
 scanf("%d",&c);
 return c;
}
void main()
{
 int queue[10];
 int front=-1,rear=-1;
 int c,item;
 while(1)
 {
  c=menu();
  switch(c)
  {
   case 1:
    printf("Enter item to insert: ");
    scanf("%d",&item);
    push(queue,&front,&rear,item);
    break;
   case 2:
    item=pop(queue,&front,&rear);
    if(item!=-1)
    {
     printf("%d has been deleted...",item);
    }
    break;
   case 3:
    display(queue,front,rear);
    break;
   case 4:
    exit(0);
   default:
    printf("\nWrong choice");
  }
 }
}

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