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cpointersdereference

Regarding dereferencing a pointer while using in linked lists

Here I have tried to create a linked list and create a function which adds any given number to the staring of the linked list.

#include <stdio.h>
#include <stdlib.h>
struct Node{
    int data;
    struct Node* next;
};
struct Node* head=NULL;

void Add(int n){
    head=(struct Node*)malloc(sizeof(struct Node));
    head->data=n;
    head->next=NULL;
    return;
}

Now my doubt is, here we have defined head to be a pointer variable of datatype struct Node. In Add function, we have assigned the address of new memory allocated to head pointer variable.

But when we are writing head->data=n, why are we not dereferencing head first, since head was a pointer variable, so it stores address, and to store variables like data, why shouldn't it be *head->data? Similar for *head->next=NULL.

Solution

  • The operator -> is already a dereferencing operator. head->data is equivalent to (*head).data.