Implementing Queue in C. Using Linked List

/* Implementing Queue in C. Using Linked List */

#include <stdio.h>
#include <stdlib.h>

struct Node
{
    int data;
    struct Node* next;
}*front = NULL, *rear = NULL;

void insert(int value)//enqueue
{
    struct Node* newNode;
    newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = value;
    newNode->next = NULL;
    if (front == NULL)
        front = rear = newNode;
    else
    {
        rear->next = newNode;
        rear = newNode;
    }
    printf("\nInsertion is Successful!!!\n");
}

void delete()//dequeue
{
    if (front == NULL)
        printf("\nQueue is Empty!!!\n");
    else
    {
        struct Node* temp = front;
        front = front->next;
        printf("\nDeleted element: %d\n", temp->data);
        free(temp);
    }
}

void print()
{
    if (front == NULL)
        printf("\nQueue is Empty!!!\n");
    else
    {
        struct Node* temp = front;
        while (temp->next != NULL) {
            printf("%d--->", temp->data);
            temp = temp->next;
        }
        printf("%d--->NULL\n", temp->data);
    }
}

int main()
{
    int choice, value;
    printf("\n:: Queue Implementation using Linked List ::\n");
    while (1)
    {
        printf("\n****** MENU ******\n");
        printf("1. Insert\n2. Delete\n3. Print\n4. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        switch (choice)
        {
        case 1: printf("Enter the value to be insert: ");
            scanf("%d", &value);
            insert(value);
            break;
        case 2: delete(); break;
        case 3: print(); break;
        case 4: exit(0);
        default: printf("\nWrong selection!!! Please try again!!!\n");
        }
    }
}


/*
Output:

::Queue Implementation using Linked List ::

****** MENU******
1. Insert
2. Delete
3. Print
4. Exit
Enter your choice : 1
Enter the value to be insert : 10

Insertion is Successful!!!

******MENU * *****
1. Insert
2. Delete
3. Print
4. Exit
Enter your choice : 1
Enter the value to be insert : 20

Insertion is Successful!!!

******MENU * *****
1. Insert
2. Delete
3. Print
4. Exit
Enter your choice : 2

Deleted element : 10

* *****MENU * *****
1. Insert
2. Delete
3. Print
4. Exit
Enter your choice : 3
20--->NULL

* *****MENU * *****
1. Insert
2. Delete
3. Print
4. Exit
Enter your choice : 4
*/