Thread: Linked List

Hey, I am having problem running this simple link list program on mingw compiler from Codelite.I am not getting any output. Can any body help...
Here is the <code>:

Code:

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

struct list_el
{
	int val;
	struct list_el *next;
};

typedef struct list_el item;

int main(int argc, char **argv)
{

	item *curr, *head;
	int i;
	
	 head =NULL;
	 
	 for(i=1; i<=5; i++)
	 {
		 
		 curr = (item*)malloc(sizeof(item));
		 curr->val = i;
		 
		 curr->next = head;
		 curr = head;
	 }
	  curr = head;
	  
	  
	 while(curr)
	  {
		  
		  printf("\n %d",curr->val);
		  curr = curr->next;
	  }
	
	return 0;
}

Try this:

Code:

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

struct list_el
{
	int val;
	struct list_el *next;
};

typedef struct list_el item;

int main(int argc, char **argv)
{
	item *curr, *head;
	int i;
	head = (item*)malloc(sizeof(item));
	curr = head;
	for(i=1;i <= 5;i++)
	{
		curr->next = (item*)malloc(sizeof(item));
		curr->val = i;
		curr = curr->next;
	}
	curr = head;
	while(i--)
	{
		printf("\n %d",curr->val);
		curr = curr->next;
	}
	return 0;
}

It'd be harder to explain why what you have is wrong. Compare yours to this and ask on anything you don't understand.

in the for, the last statement, it should be head = curr;

Thanks for the complete code. It worked for me!!
So does it mean that linked list elements can be accessed from the beginning only and not from the end??

I am trying to construct an linked list of 5 members in the following snippet but the snipet just prints two elements. Can anybody point out where am I going wrong:

Code:

int main(int argc, char **argv)
{
	struct node *head, *curr, *temp;
	int i;
	head = (struct node*)malloc(sizeof(struct node));
	
	curr = head;
	
	for(i=1;i<=5;i++)
	{
	
	curr -> next = (struct node*)malloc(sizeof(struct node));
	curr -> x= i;
	temp=curr;
	curr = curr->next;
	}
	temp->next =0;
	
	
	
	//Display members
	curr = head;

	
	if(curr->next!=0)
	{
		printf("\n %d", curr->x);
		curr = curr->next;
	}
	printf("\n %d", curr->x); // to print the last element in the list
			 
		return 0;
}

if(curr->next!=0) should be a while.

you are not doing any looping when you are printing the list.

Are you trying to insert at head or tail of the list??

Thank you for the help. I replaced 0 with NULL and if with while and it now prints all the 5 members in the linked list.
After completing the 5 iterations, the temp points to NULL but where how should curr points so as to avoid memory leaks ?

Also have I correctly freed the memory in the following snippet?

Code:

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

struct node
{
	int x;
	node *next;
};
int main(int argc, char **argv)
{
	struct node *head, *curr, *temp;
	int i;
	head = (struct node*)malloc(sizeof(struct node));
	
	curr = head;
	
	for(i=1;i<=5;i++)
	{
	
	curr -> next = (struct node*)malloc(sizeof(struct node));
	curr -> x= i;
	temp=curr;
	curr = curr->next;
	}
	temp->next =NULL;
	
	
	
	//Display members
	curr = head;

	
	while(curr->next!=NULL)
	{
		printf("\n %d", curr->x);
		curr = curr->next;
	}
	printf("\n %d", curr->x); // to print the last element in the list
	
	free(curr->next);
			 
		return 0;
}

this might be what you want in the very begining

Code:

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

struct list_el
{
	int val;
	struct list_el *next;
};

typedef struct list_el item;

int main(int argc, char **argv)
{

	item *curr, *head;
	int i;
	
	 head =NULL;
	 
	 for(i=1; i<=5; i++)
	 {
		 
		 curr = (item*)malloc(sizeof(item));
		 curr->val = i;
		 
		 curr->next = head;
		 head = curr;
		
	 }
	  head = curr;
	  
	  
	 while(curr)
	  {
		  
		  printf("\n %d",curr->val);
		  curr = curr->next;
	  }
	
	return 0;
}

The code I posted before was a fixed version from #1 post.
At least, the result is printing
5
4
3
2
1
in the command line window.
The way of inserting node was not great.
The order of the linked list would be reversed from the inputting order.
But..I mean it still a kind of way to create a linked list. It might be called "insertation at head "or sth .etc.

by the way, I do not understand leaking memory problem. I know I have not free the list I just created(I don't need this time). what else?