queue.c

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#include <stdio.h>
#include <stdlib.h>
#include "queue.h"
 
 
void initQueue(struct Queue *queue)
{
    queue -> front = NULL;
    queue -> rear = NULL;
}
 
 
int isEmpty(struct Queue *queue)
{
    if (queue->front == NULL)
        return 1;
    else
        return 0;
}
 
 
void enqueue(struct Queue *queue, int data)
{
    struct Node *newNode = (struct Node *)malloc(sizeof(struct Node));
    newNode -> data = data;
    newNode -> next = NULL;
    
    if (isEmpty(queue)) {
        queue -> front = newNode;
        queue -> rear = newNode;
    }
    else {
        queue -> rear -> next = newNode;
        queue -> rear = newNode;
    }
}
 
 
int dequeue(struct Queue *queue)
{
    struct Node *delNode;
    int popdata;
    
    // Raise exception if queue is empty
    if (isEmpty(queue)){
        printf("Empty Queue\n");
        return -1;
    }
 
    // 
    delNode = queue -> front;
    popdata = delNode -> data;
    queue -> front = queue -> front -> next;
 
    free(delNode);
 
    return popdata;
}