strncmp in Linked List

Question

This program should allow the user to input some names (until the user wishes to continue.) and then display those names in ascending order. I have used the strncmp function in comparing the char arrays. But when this is run, only the 1st and last name of the sorted name list is given as the output (which means, the list was sorted). But I cannot find out why the names in between them aren't displayed. Please help me! Thank you.

#include <stdio.h>
#include <malloc.h>
#include <string.h>

char name[10];
int place;

struct node
{
  char nm[10];
  struct node *next;
}*newnode, *prev, *temp, *display, *current, *list;

void createlist()
{
  list = NULL;
}
;

void insert()
{
  newnode = (struct node*) malloc(sizeof(struct node));

  printf("Enter the Name: ");
  scanf("%s", &name);
  strncpy(newnode->nm, name, 10);
  newnode->next = NULL;

  if (list == NULL )
  {
    list = newnode;
  }
  else if (strncmp(name, list->nm, 10) < 0)
  {
    newnode->next = list;
    list = newnode;
  }
  else
  {
    temp = list;

    place = 0;

    while (temp != NULL && place == 0)
    {
      if (strncmp(name, temp->nm, 10) >= 0)
      {
        prev = temp;
        temp = temp->next;
      }
      else
      {
        place = 1;
      }
      newnode->next = prev->next;
      prev->next = newnode;
    }
  }
}

void displayname()
{
  if (list == NULL )
    printf("\n\nList is empty");
  else
  {
    display = list;
    while (display != NULL )
    {
      printf("%s\n", display->nm);
      display = display->next;
    }
  }
}

int main()
{

  char choice;
  choice == 'y';

  createlist();
  do
  {
    insert();
    printf("Do you want to continue? ");
    scanf("%s", &choice);
  } while (choice = 'y' && choice != 'n');

  displayname();
}

Answer 1

In your insert function, you are useing

newnode->next = prev->next;
prev->next = newnode;

use like

newnode->next = temp;
prev->next = newnode;

[EDIT]

Use your insert function like this.

void insert()
{
    newnode = (struct node*) malloc(sizeof(struct node));

    printf("Enter the Name: ");
    scanf("%s", &name);
    strncpy(newnode->nm, name, 10);
    newnode->next = NULL;

    if (list == NULL )
    {
        list = newnode;
    }
    else if (strncmp(name, list->nm, 10) < 0)
    {
        newnode->next = list;
        list = newnode;
    }
    else
    {
        temp = list;

        prev = NULL;
        // prev is a global variable, So assign it to NULL each time, Otherwise it will keep old value.
        while (temp != NULL)
        {
            if (strcmp(name, temp->nm) >= 0)
            {
                prev = temp;
                temp = temp->next;
            }
            else
            {
              break;

            }
        }
        newnode->next = temp;
        prev->next = newnode;
    }
}

Now do remember one thing, In your code,

1. in main() your are doing

   choice == 'y'; that is not assignment. You should use

   choice = 'y';

2. in your main(), in do{}while() your are using

   while (choice = 'y' && choice != 'n'); choice ='y' is assignment, not comparison. use like this

   while (choice == 'y' && choice != 'n');

3. in main(), you are using

   scanf("%s", &choice); // choice is a char, you are trying to have string (%s) here. That will memory corruption So use it like this,

   choice = getche();

Answer 2

change your else in the insert function to the following:

else
{
    temp = list;
    while(temp !=NULL && strncmp(temp->nm,name,10)<0)
    {
        prev=temp;
        temp=temp->next;
    }
    if(temp==NULL)
        prev->next=newnode;
    else
    {
        newnode->next=temp;
        prev->next=newnode;
    }

}