Link Linked Lists in C - c

Question

I am trying to create an (ordered) linked list of (ordered) linked lists. The list-of-list links are carried by the first nodes of its member lists. I am trying to achieve this via the following code, but my program crashes right after I try to insert the second node into the list of lists.
Here's a schematic of the data structure I am trying to construct:
Code:
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
struct node{
int number;
struct node*next;
struct node*lsnext;
};
typedef struct node Node;
Node* insertValue(Node * list, int value);
void display(Node*);
Node* insertArr(Node * list, int value);
int main()
{
Node *globalList = NULL, *lists,*start,*save;
int nbrOfLists, listNo, nbrOfVal, valNo, val;
printf("\n Enter the number of lists:");
scanf("%d", &nbrOfLists);
if(nbrOfLists < 0)
return -1;
for(listNo = 0; listNo < nbrOfLists; listNo++)
{
printf("\n\n Enter the number of inputs to the list %d: \n ",listNo+1);
scanf("%d", &nbrOfVal);
lists = NULL;
for(valNo = 0; valNo < nbrOfVal; valNo++)
{
printf("Enter node value %d:", valNo+1);
scanf("%d", &val);
// Here we insert the value in both lists
lists= insertValue(lists, val);
globalList = insertValue(globalList, val);
}
start=lists;
if(listNo==0){
save=start;
}
start=start->lsnext;
printf("\n The list %d is: ",listNo+1);
display(lists);
}
printf("\n\n The final list is: ");
display(globalList);
printf("The first list is");
display(save);
printf("The second list is");
display(save->lsnext); // CRASHES HERE
return 0;
}
Node* insertValue(Node * list, int value)
{
Node *newNode, *m;
newNode = malloc(sizeof(Node));
newNode->number=value;
if(list == NULL)
{
newNode->next=NULL;
return newNode;
}
if(value < list->number)
{
newNode->next = list;
return newNode;
}
m = list;
while(m->next)
{
if(value < m->next->number)
break;
m = m->next;
}
newNode->next = m->next;
m->next = newNode;
return list;
}
void display(Node*nodex){
while(nodex)
{
printf("%d ->",nodex->number);
nodex=nodex->next;
}
}
What is causing my error?

Answer 1

Your insertArr() function is wrong. Even its signature is wrong. Instead of linking together the first nodes of existing lists, it creates a perpendicular list of separate nodes. Note in particular that it accepts a value where it needs instead to accept the head node of a list.
Moreover, even the circumstances under which you call that function are wrong. You seem to try to link the initial head nodes of each list, but the head node may change as you add values. You must wait until you have a full list before you know what its final head node is; only then can you link that list into your list of lists.
Edit: I had first asserted that your problem was failure to initialize the lsnext members of your nodes. That would be correct if your insertArr() function were actually accepting nodes created by insertValue() as its second argument, as it should, but it is not correct for the code presented. The actual problem is a consequence of the issue described in my first paragraph, that insertArr() creates a separate list of separate nodes. In particular, those separate nodes do not have their next pointers initialized.