adding nodes into singly-linked list

Question

I am trying to learn linked lists.I just wrote a program illustrating a linked list but it doesn't seem to work.Here's the code:

#include <iostream>
using namespace std;

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

int main(int argc, const char * argv[])
{
    node* trav;
    node* root;
    root = new node;

    trav = root;

    trav -> data = 4;
    trav -> next = new node;

    trav -> data = 5;
    trav -> next = new node;

    trav -> data = 6;
    trav -> next = 0;
    trav = root;

    while (trav!=0) {
        std::cout<<trav->data;
        trav=trav->next;
    }
}

I want root to point to the first node but it seems to copy trav 's data as we go further into the program. Any idea what's wrong?
Thanks

Answer 1

In this code:

trav = root;

trav -> data = 4;
trav -> next = new node;

trav -> data = 5;
trav -> next = new node;

you are not changing the trav pointer, which means you are overwriting its members. After creating new node by calling trav->next = new node; you should "move" to the next node by calling:

trav = trav-> next;

Answer 2

You never do

trav = trav -> next;

When you fill up the list. You don't move in the list, and just keep modifying the root.

Answer 3

You are missing trav = trav -> next after trav -> next = new node ; in other words, you create a new node but you never actually "step" there.