Queue_01_LQueue

//Linear Queue

#include<conio.h>
#include<stdio.h>
#define MAX 3

//Global Variable
int queue [MAX];
int front=-1, rear=-1;

//UDF Function
void insert();
int Delete_Element();
void display();

void main()
{
    int op, val;
    clrscr();
    do
    {
        getch();
        clrscr();

        printf("\n -------------------------");
        printf("\n -------Linear Queue------");
        printf("\n -------------------------");
        printf("\n 1. Insert");
        printf("\n 2. Delete");
        printf("\n 3. Display");
        printf("\n 4. Exit");
        printf("\n -------------------------");
        printf("\n Maximum 3 Value Get");
        printf("\n -------------------------");
        printf("\n Enter Choice : ");
        scanf("%d", &op);
        printf(" -------------------------");
        switch(op)
        {
            case 1:
                insert();
            break;

            case 2:
                val=Delete_Element();
                if(val !=-1)
                {
                    printf("\n The Number Deleted : %d", val);
                }
            break;

            case 3:
                display();
            break;
        }
    }while(op!=4);
    getch();
}

//UDF Function Declation
void insert()
{
    int num;
    printf("\n Enter The Number to Be Inserted in Queue : ");
    scanf("%d", &num);

    if(rear == MAX-1)
    {
        printf("\n Linear Queue is Overflow");
    }
    else
    {
        if(front == -1 && rear == -1)
        {
            front = rear = 0;
        }
        else
        {
            rear++;
        }
        queue[rear]=num;
    }
}

int Delete_Element()
{
    int val;
    if(front == -1 || front > rear)
    {
        printf("\n Linear Queue is Underflow");
        return -1;
    }
    else
    {
        val=queue[front];
        front++;
        if(front > rear)
        {
            front = rear = -1;
        }
        return val;
    }
}

void display()
{
    int i;
    //printf("\n ");
    if(front == -1 || front > rear)
    {
        printf("\n Linear Queue is Empty.");
    }
    else
    {
        for(i=front; i<=rear; i++)
        {
            printf("\n Element : %d", i);
            printf(" -> %d", queue[i]);
        }
    }
}