How to pass a struct by reference?

Question

I can't figure it out, this is what I have so far.

But the function Enqueue() is not changing the Head & Tail objects from the main method.

How do I do this?

#include <stdio.h>

typedef struct queuenode{
    int data;
    struct queuenode *next;
} Queue_type;

void Enqueue( Queue_type *head, Queue_type *tail , int item)
{
    Queue_type *temp;
    temp->data = item;
    temp->next = NULL;
    if (tail == NULL){//if first node
        head=temp;
        tail=temp;
    }
    else{
        tail->next = temp;
        tail = temp;
    }
}

void main(void)
{
    Queue_type *Head;
    Queue_type *Tail;

    Head = NULL;
    Tail = NULL;

    printf("\n[*]Enter Number to Enqueue : ");
    scanf("%d", &item);
    Enqueue(Head, Tail, item);

}

There is an additional issue of not allocating memory for your Queue_type objects. — , Nov 20 '12 at 17:57
I don't see where you are passing anything by reference. Can you be more specific? Do you mean to pass a pointer to it? — Jonathan Wood, Nov 20 '12 at 17:57
If you happen to pass by the options dialog set your editor to expand tabs to spaces... — 6502, Nov 20 '12 at 17:59

score 8 · Accepted Answer · edited May 23 '17 at 11:54

8

How to pass a pointer by reference? Pass it by reference:

void Enqueue( Queue_type *&head, Queue_type *&tail , int item)

How to pass a struct by reference?

1 Answers1