Queue Operation in Data-Structure(Enqueue and Dequeue)

Queue: Like stack ,queue is an ordered collection of homogeneous data elements in contrast with the stack,here insertion and deletion operations take phase as two extreme ends.

Queue Operation in Data-Structure(Enqueue and Dequeue) or
FIFO(First In First Out)
-------------------------------------------------------------------
#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;
printf(">>> c program to implement queue operations <<<");
do
{
printf("\n\n 1.Insert an element");
printf("\n 2.Delete an element");
printf("\n 3.Display queue");
printf("\n 4.Exit");
printf("\n Enter your choice: ");
scanf("%d",&option);
switch(option)
{
case 1: insert_element();
break;
case 2: delete_element();
break;
case 3: display_queue();
break;
case 4: return 0;
}

}while(option!=4);

}
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]);
}
}
}

(By:shahimtiyaj)