Normal_Queue.c

#include <stdio.h>

#define MAX 10

int queue[MAX];
int front = 0, rear = -1;

/* Function declarations */
void insert(void);
void delete1(void);
void display(void);

int main(void)
{
    int choice;

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

        switch (choice)
        {
            case 1:
                insert();
                break;

            case 2:
                delete1();
                break;

            case 3:
                display();
                break;

            case 4:
                printf("Exiting...\n");
                break;

            default:
                printf("Wrong Choice\n");
        }
    } while (choice != 4);

    return 0;
}

void insert(void)
{
    int n;

    if (rear == MAX - 1)
    {
        printf("Queue Overflow\n");
    }
    else
    {
        printf("Enter the element: ");
        scanf("%d", &n);
        rear++;
        queue[rear] = n;
        printf("%d inserted into queue\n", n);
    }
}

void delete1(void)
{
    int n;

    if (rear < front)
    {
        printf("Queue is Empty\n");
    }
    else
    {
        n = queue[front];
        front++;
        printf("Deleted element is %d\n", n);
    }
}

void display(void)
{
    int i;

    if (rear < front)
    {
        printf("Queue is Empty\n");
    }
    else
    {
        printf("Queue elements are:\n");
        for (i = front; i <= rear; i++)
        {
            printf("%d\n", queue[i]);
        }
    }
}