Inserting in a Linked List in C++ [closed] - c++

Question

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 8 years ago.
Improve this question
Please help me with my code. I am trying to insert in a singly linked list.My code is compiling but it is giving a run time error.I am not able to understand where i have gone wrong.Here goes my code :-
#include <iostream.h>
#include <stdio.h>
using namespace std;
struct node
{
int info;
struct node* next;
};
typedef struct node* nodeptr;
void insert(nodeptr p,int x);
void print(nodeptr p);
int main()
{
nodeptr head;
head = NULL;
int num;
do
{
cout<<"ENTER A NUMBER(0 to terminate) :-\n";
cin >>num;
insert(head,num);
}
while (num != 0);
print(head);
}
void insert(nodeptr p,int x)
{
nodeptr tmp = new node;
tmp -> info = x;
tmp -> next = NULL;
nodeptr current;
current = p;
if (p == NULL)
{
p = tmp;
}
if (x < p -> info)
{
tmp->next = p;
p = tmp;
}
while((current->next != NULL) && (x >= (current->next)->info))
{
current = current -> next;
}
tmp->next = current->next;
current->next = tmp;
}
void print(nodeptr p)
{
nodeptr current;
current = p;
while(current != NULL)
{
int tmp = current->info;
cout << tmp;
current = current->next;
}
}

Answer 1

First of all, you never assign anything to head, so print(head) will not print anything.
Second, that last while in the main is useless.
Third:
nodeptr insert(nodeptr head, int x)
{
nodeptr tmp = new node;
tmp -> info = x;
tmp -> next = NULL;
nodeptr prec = null;
nodeptr current = head;
while(current != null && x < current->info)
{
prec = current;
current = current -> next;
}
tmp->next = current;
if(prec != null)
prec->next = tmp;
else
return tmp;
return head;
}
and in the main
head = insert(head, num);
When dealing with pointers, always try to keep things separated: first seek, then modify.