Linked List implementation of quque

linked_list_queue.c

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

struct node
{
	int val;
	struct node* next;
};

void enqueue(struct node**,struct node **,int);
void dequeue(struct node**,struct node **);
void traverse(struct node*,struct node*);
void free_queue(struct node*);


int main()
{
	int key;
	struct node *front=NULL,*rear=NULL;
	FILE *fp;
	fp=fopen("input","r");
	fscanf(fp,"%d",&key);
	while(!feof(fp))
	{
		enqueue(&front,&rear,key);
		fscanf(fp,"%d",&key);
	}
	traverse(front,rear);
	dequeue(&front,&rear);
	dequeue(&front,&rear);
	traverse(front,rear);
	free_queue(front);
	return 0;
}
	
void enqueue(struct node** front,struct node** rear,int num)
{
	struct node* newnode=malloc(sizeof(struct node));
	newnode->val=num;
	newnode->next=NULL;
	if(*front==NULL)
		*front=*rear=newnode;
	else
	{
		(*rear)->next=newnode;
		(*rear)=newnode;
	}
}

void dequeue(struct node** front,struct node** rear)
{
	struct node* temp=NULL;
	if(*front==*rear)
	{
		temp=*front;
		*front=*rear=NULL;
	}
	else if(*front!=NULL)
	{
		temp=*front;
		*front=(*front)->next;
	}
	if(temp!=NULL)
		free(temp);
}

void free_queue(struct node* front)
{
	while(front!=NULL)
	{
		free(front);
		front=front->next;
	}
}

void traverse(struct node* front,struct node* rear)
{
	struct node* temp=front;
	while(temp!=NULL)
	{
		printf("%d",temp->val);
		if(temp!=rear)
			printf("--->");
		else
			printf("\n");
		temp=temp->next;
	}
}