Link list in c. How do I access the value inside the link list?

Question

I've made a new node. How do I refer node->question->question, node->question->options[], node->question->correctans and node->question->difficulty_level

struct node {

    node *prev;

    node *next;

    int count; 

    Question question[];

};
struct Question{

    String question;

    String[] options;

    String correctans;

    int difficulty_level;
}

"How do I refer"? What is `Question question[]` supposed to be? Which question did you wish to "refer"? — Lightness Races in Orbit, Dec 27 '13 at 19:15
@chris - I know this isnt valid c++, I wrote the pseudocode. Lightness- Questiion question[] is an array of objects of class question — Praful Bagai, Dec 27 '13 at 19:20
@user1162512: No, it's not. Funny how you moved the `[]` for `String[] options`. As it happens, _neither_ is correct. But it shows that you're not being very diligent with your programming, just throwing characters around willy-nilly... — Lightness Races in Orbit, Dec 27 '13 at 19:22
How do I represent it then? I'm actually a python guy. Please help. — Praful Bagai, Dec 27 '13 at 19:22
thats why I said I'm just writing a pseudo-code. I've minimum knowledge of C. Please rectify and tell where I'm wrong — Praful Bagai, Dec 27 '13 at 19:25
@user1162512: **Stop!** Learn C++, with [a good book](http://stackoverflow.com/q/388242/560648). Don't try to do this by guessing. — Lightness Races in Orbit, Dec 27 '13 at 19:42

score 0 · Answer 1 · answered Dec 27 '13 at 19:36

0

'->' is a pointer dereference. Since you have an array of objects in your node (and not just pointer to them), the correct way to access those would be 'node.question[x]'. The same applies for your Question struct, i.e. node.question[0].question would yield the question string of the first question saved in this nodes array (if this was valid c code...).

Hope this helps, let me know if anything is unclear to you.

answered Dec 27 '13 at 19:36

Andreas A.

11
3

Actually each node is pointing to an array of objects of structure Questions. How would I do now? Sorry for causing trouble. – Praful Bagai Dec 27 '13 at 19:48

Gibby · Accepted Answer · 2013-12-27T20:05:58.677

0

I am not certain what you are asking but I think this is what your looking for:

#include <string.h>
#include <iostream>
using namespace std;

struct Question{

    string *question;

    string  *options [4];

    string correctans;

    int difficulty_level;
};

struct node {

    node *prev;

    node *next;

    int count; 

    Question *question[4]; 

}n;

int main(){
    Question *q;
    Question qu;

    q->question = new string("This is a question"); // assign some values
    q->options[0]= new string("The first option");
    q->difficulty_level = 4;

    qu.question = new string("another question");
    qu.options[0]= new string("The second option");
    qu.difficulty_level = 5;

    n.question[0] = q;
    n.question[1] = &qu;
    //print the assigned values
    cout << "Question 1 question: " <<  *n.question[0]->question << endl;
    cout << "Question 1 Option 1: "<<*n.question[0]->options[0] << endl;
    cout << "Question 1 dificulty: "<<n.question[0]->difficulty_level << endl;

    cout << "Question 2 question: " <<  *n.question[1]->question << endl;
    cout << "Question 2 Option 1: "<<*n.question[1]->options[0] << endl;
    cout << "Question 2 dificulty: "<<n.question[1]->difficulty_level << endl;

}

edited Dec 27 '13 at 20:05

answered Dec 27 '13 at 19:39

Gibby

458
1
4
14

I'm extremely sorry for causing you trouble because I being a python guy. the problem is actually each node is pointing to an array of objects of structure Questions. So, I dont think what you wrote is the solution for my problem. Is it? `q->question` in my case wont be correct. Isnt it? – Praful Bagai Dec 27 '13 at 19:46
I will alter it to answer your question. – Gibby Dec 27 '13 at 19:52
Ya. I got it, thats why deleted the comment. – Praful Bagai Dec 27 '13 at 20:13
Why did you made questions and options as pointers? Any specific reason? – Praful Bagai Dec 27 '13 at 20:16
So, can I make them as normal strings? – Praful Bagai Dec 27 '13 at 20:18
I prefer not to mess around with literals but if you want to go ahead. – Gibby Dec 27 '13 at 20:19

Link list in c. How do I access the value inside the link list?

2 Answers2