Question

I’m trying to make a code that allows me to enter a tree node and then indicate its preorder traversal, but do not understand what happens. What am I doing wrong?

This is my code:

#include <stdio.h>
#include<iostream>
#include<queue>
#define MAX 100
#include <vector>
#include <stdlib.h>

typedef struct node {
    struct node *parent;
    struct node *left;
    struct node *right;

    int value;
} Node;

typedef struct tree {
    Node *root;
} Tree;

void findPlace(Node *_toAdd, Node *_current) {
    // set this node to the parent so we dont have to do it later (may change next recursion)
    _toAdd->parent = _current;

    // compare value of node we're adding to current node
    if(_toAdd->value < _current->value)
        // add the element to the left subtree
        if(_current->left == NULL)          // if no left subtree yet, add it right here
            _current->left = _toAdd;
        else                                        // otherwise continue recursion to left subtree
            findPlace(_toAdd, _current->left);
    else
        // add the element to the right subtree
        if(_current->right == NULL)     // if no right subtree yet, add it right here
            _current->right = _toAdd;
        else                                        // otherwise, continue recursing to the right subtree
            findPlace(_toAdd, _current->right);
}

Node *addNode(int _val, Tree* _tree) {
    Node *newNode = (Node *)malloc(sizeof(Node));
    newNode->value = _val;

    // if the tree is empty, this is the new root
    if(_tree->root == NULL)
        _tree->root = newNode;

    // otherwise, we need to find the right place to put it
    else
        findPlace(newNode, _tree->root);

    // return reference to the node
    return newNode;
}


void preOrder(Node *);


int main() {
    // create a tree to fool around with
    Tree *myTree = (Tree *)malloc(sizeof(Tree));

    // Add some values to the tree
    addNode(7, myTree);
    addNode(3, myTree);
    addNode(7, myTree);
    addNode(11, myTree);
    addNode(6, myTree);
    addNode(8, myTree);
    addNode(12, myTree);
    addNode(0, myTree);
    addNode(2, myTree);
    addNode(9, myTree);

    printf("Pre-Order Traversal: "); preOrder(myTree->root); printf("\n");



    return 0;
}

void preOrder(Node *_root)
{
    printf("%d ", _root->value);
    if(_root->left != NULL)
        preOrder(_root->left);
    if(_root->right != NULL)
        preOrder(_root->right);
}

It is assumed that calling preorder action, it should print the tree in that order but the program simply terminates and does not print anything, im stuck with this please help me, and excuse my English

Answer 1

I think your issue is that you don’t have anything stalling the exiting of the program…just use cin

int x;
cin >> x;

return 0;