#Preorder function not displaying

1 messages · Page 1 of 1 (latest)

pale vapor
# 
#include <iostream>
#include <queue>

struct Node
{
public:
    Node* lchild;
    int data;
    Node* rchild;
}*root = NULL;

void createB()
{
    int x;

    Node* t, * p = new Node;
    std::queue<int*> q;
    
    std::cout << "Enter the value of root : ";
    std::cin >> x;

    Node *root = new Node;
    root->data = x;
    root->lchild = root->rchild = NULL;

    q.push(&root->data);

    while (!q.empty())
    {
        p->data = *q.front();
        q.pop();
        std::cout << "Enter Left Child of " << p->data << " : ";
        std::cin >> x;

        if (x != -1)
        {
            t = new Node;
            t->data = x;
            t->lchild = t->rchild = NULL;
            p->lchild = t;

            q.push(&t->data);
        }

        std::cout << "Enter Right Child " << p->data << " : ";
        std::cin >> x;

        if (x != -1)
        {
            t = new Node;
            t->data = x;
            t->lchild = t->rchild = NULL;
            p->rchild = t;

            q.push(&t->data);
        }
    }
    
}

void preorder(Node* p)
{
    while(p)
    {
        std::cout << p->data << ' ';
        p->lchild;
        p->rchild;
    }
}
int main()
{
    createB();
    preorder(root);
}
prisma copperBOT
#

When your question is answered use !solved to mark the question as resolved.

Remember to ask specific questions, provide necessary details, and reduce your question to its simplest form. For tips on how to ask a good question run !howto ask.

kindred heath
#

p->lchild;
p->rchild; wha!??1

#

why should it run? it's your job to explain why you think your code should work.. so we can see where you are going wrong.

pale vapor
#

The createB() function would create Tree
Then after creating the tree I need to display it using preorder function

turbid olive
#

don't cross post AngrySock

pale vapor
#

here is the image of the tree

turbid olive
#

anyways I explained in #cpp-help-text

#

close this

kindred heath
#

when can kinda see 'what' it's supposed to do.. its just a loop and cout. so now answer 'why'. comment every line of code with what you think it's going to do

#

(every == start with the ones that arent' doing what you want)

turbid olive
#

I guess you deleted the other one now...

#

Node *root = new Node;
you are hiding the outer root variable here

#

so your root is nullptr when you do the print

pale vapor
turbid olive
#

btw use nullptr instead of NULL for pointers

pale vapor
#

!solved