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

struct node{
	int value;
	struct node*next;
};

typedef struct node Node;

int main()
{
	int input=0;
	Node*list, *tmp;
	list=tmp=NULL;
	while(input != -1)
	{

	fprintf(stdout, "Enter a value (-1 to end): ");
	fscanf(stdin, "%d", &input);

	if(input != -1)
	{
		if(list == NULL)
		{
			list=tmp=(Node*)malloc(sizeof(Node));
			tmp->next=NULL;
			list->value=input;
		} else {
			tmp->next=(Node*)malloc(sizeof(Node));
			tmp->next->next=NULL;
			tmp->next->value=input;
			tmp=tmp->next;
		}
	}
}
	tmp=list;
	input=0;

	while(tmp != NULL)
	{
		fprintf(stdout, "%d ->",tmp->value);
		tmp=tmp->next;
		input=input++;
	}

	fprintf(stdout, "NULL\n");
	//insert into list
	fprintf(stdout, "Which node would you like to insert before? ");
	fscanf(stdin, "%d", &input);
	int seeker;
	tmp=list;
	Node*tmp2=NULL;

	for(seeker=0; seeker < (input-1); seeker++)
	{
		tmp=tmp->next;
	}
	fprintf(stdout, "Eneter a value to insert: ");
	fscanf(stdin, "%d", &input);
	tmp2=(Node*)malloc(sizeof(Node));
	tmp2->value=input;
	tmp2->next=tmp->next;
	tmp->next=tmp2;

return(0);

}</code>