CODEWITHSUNDEEP
cdata-structureslinked-listsingly-linked-list
abhijeet namdhari
abhijeet namdhari

Reputation: 65

linked list print function is not working

This program runs without error but it doesn't print anything. I couldn't figure out the error.

I'm learning data structure in C, is this a good practice to learn data structure?

Thanks in advance!!!!!!

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


typedef struct Node
 {
   int data;
   struct Node *next;
 }list_node;


 list_node* push(list_node* head_r, int new_data)
 {
    list_node* new_Node = (list_node*)malloc(sizeof(list_node));

    new_Node->data  = new_data;
    new_Node->next = head_r;
    head_r = new_Node;
    return head_r;
  }

void Print(list_node* head_r)  
 {
   while(head_r)
    {
      printf("%d\n", head_r->data);
      head_r = head_r->next;
    }

  }


int main()
 {

    list_node* l_list = NULL;
  push(l_list, 1);
  push(l_list, 2);
  push(l_list, 6);
  push(l_list, 8);
  push(l_list, 7);
  push(l_list, 3);
  push(l_list, 4);

  printf("Given linked list \n");
  Print(l_list);

  return 0; 
}

Upvotes: 0

Views: 79

Answers (2)

Embedded Software Engineer
Embedded Software Engineer

Reputation: 4906

Your list is empty because push returned value is not used

Your main should like this:

int main()
 {

    list_node* l_list = NULL;
  l_list = push(l_list, 1);
  l_list = push(l_list, 2);
  l_list = push(l_list, 6);
  l_list = push(l_list, 8);
  l_list = push(l_list, 7);
  l_list = push(l_list, 3);
  l_list = push(l_list, 4);

  printf("Given linked list \n");
  Print(l_list);

  return 0; 
}

or you can pass list by reference and for this time your code look like this:

void push(list_node** head_r, int new_data)
 {
    list_node* new_Node = (list_node*)malloc(sizeof(list_node));

    new_Node->data  = new_data;
    new_Node->next = *head_r;
    *head_r = new_Node;
  }

int main()
 {

    list_node* l_list = NULL;
  push(&l_list, 1);
  push(&l_list, 2);
  push(&l_list, 6);
  push(&l_list, 8);
  push(&l_list, 7);
  push(&l_list, 3);
  push(&l_list, 4);

  printf("Given linked list \n");
  Print(l_list);

  return 0; 
}

Upvotes: 3

atturri
atturri

Reputation: 1153

Change the lines in the main function for these:

l_list = push(l_list, 1);
l_list = push(l_list, 2);
l_list = push(l_list, 6);
l_list = push(l_list, 8);
l_list = push(l_list, 7);
l_list = push(l_list, 3);
l_list = push(l_list, 4);

You were returning a new node with push but not saving anywhere, so your list in main was always empty.

Upvotes: 2

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