Struct definition for linked lists in c++

Question

While solving questions related to linked lists in C++, the struct definition for implementation of list was given as follows.

Struct node{
  int data;
  node *next;
  node(int x) : data(x), next(NULL) {}
};

what is the significance of 3rd line : " node(int x) : data(x), next(NULL) {} ".

Accessing it as a function is giving runtime error. Please share some resources where I can get a better understanding of the topic.

P.S.- I have just shifted from C to C++.

There is a list of good C++ books [here](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list). Don't assume that C and C++ are almost the same language. — molbdnilo, Jun 18 '21 at 07:35
Be sincere to the former Java developer. I also had this question in the past. — Audrius Meškauskas, Jun 18 '21 at 07:39
Congratulations for leaving Java behind and for taking up C++. Have an upvote! — Bathsheba, Jun 18 '21 at 07:50

Aditya Singh Rathore · Accepted Answer · 2021-06-18T08:07:22.003

3

node(int x) : data(x), next(NULL) {}

This is the constructor of node. It creates a node and initializes the member data with value x.
Read more What is this weird colon-member (" : ") syntax in the constructor?

If you are from python background, then it is same as

class Node: 
    
    def __init__(self, x): 
        self.data = x
        self.next = None

struct is same as class except everything is public by default in cpp strict. struct is an object in cpp, so it needs a constructor.

Please share some resources where I can get a better understanding of the topic.

edited Jun 18 '21 at 08:07

answered Jun 18 '21 at 07:27

2

You didn't say anything about the `next` data member. – Evg Jun 18 '21 at 07:52
My bad, updated – Aditya Singh Rathore Jun 18 '21 at 08:06

1 Answers1