C Program for Circular queue using array

".C" file is available in downloadable format at :

https://drive.google.com/open?id=0ByF0OId1bLx6NmNnQVIzdFI3dGc

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Given below is the code for "C Program for Circular queue using array" :

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#include<stdio.h>
#include<stdlib.h>
#define size 50

typedef struct queue
{
int a[size];
int front;
int rear;
}ob;

ob q;

void qdelete(int*, int*); 

void insert ()
{
int ele;

printf("\nEnter the element to be inserted:\t");
scanf("%d", &ele);

if((q.rear+1)%size==q.front)
   // same as this : if((q.front==0)&&(q.rear=size-1)||(q.rear+1==q.front))
{
printf("\nQUEUE IS FULL !!\n 50 elements have been inserted, no more space :( ");
return;
}

else
 {
 if(q.rear==size-1)
  q.rear=0;
 else
  q.rear++;
 }
 q.a[q.rear]= ele;
  
 if(q.front==-1)
  {
  q.front=0;
  }
 
 printf("\n--------------------------| %d Inserted | --------------------------\n",q.a[q.rear]);
}


void qdelete(int* front, int* rear)
{
if(q.front==-1)
 {
 printf("\nQueue empty");
 return;
 }
 
else
 {
   printf("\n--------------------------| %d Deleted | --------------------------\n", q.a[q.front] );
 
  if(q.front==q.rear)
   {
   q.front=-1;
   q.rear=-1;
   }
  else
  { 
  q.front=(q.front+1)%size;

     /* same as this: 
     if(q.front==size-1)
       q.front=0;
      else
       q.front++; */
  }
 }
}

void display ()
{
int i=q.front, j=q.rear;
printf("\n--------------------------DISPLAY--------------------------\n");

 while(i!=j)
 {
 printf(" %d ", q.a[i++]);
 }

 printf (" %d", q.a[i]);
 printf("\n");
}

void main()
{
int choice;
q.front = -1;
q.rear = -1;

while(1)

 {
 printf("\n\n\n1. Add data.\n2. Delete data.\n3. Display data.\n4. Exit program.\n\nEnter your choice:\t");
 scanf("%d", &choice);

 switch(choice)
  {
  case 1: insert(); break;
  case 2: qdelete(&q.front, &q.rear); break;
  case 3: display (); break;
  case 4: exit(0);
  default: printf("\n\nHey!! Choose an option from the choices mentioned!!\n And stop testing my program!!");
  }
 }
 
}