C++ Binary Tree Works in CentOS 6 but not Mac OSX Mavericks

Question

Right now I'm dumbfounded as to why the following program appears to work fine on my CentOS 6 box, but running the compiled program results in a Seg Fault 11 on my Mac OSX. I debug on my Macbook using Eclipse and the gdb debugger with some strange results. It's a simple binary tree example:

#include <iostream>
#include <stdlib.h>

#include "binary_tree.h"

using namespace std;

struct node* newNode(int x) {
        struct node *n = (struct node*)malloc(sizeof(struct node*));
        n->x = x;
        n->left = NULL;
        n->right = NULL;

        return n;
}

struct node* insert(struct node *node, int x) {
        if(node == NULL) {
                return newNode(x);
        } else {
                if(x <= node->x) {
                        node->left = insert(node->left, x);
                        cout << "INSERTED " << x << " LEFT OF " << node->x << endl;
                } else {
                        node->right = insert(node->right, x);
                        cout << "INSERTED " << x << " RIGHT OF " << node->x << endl;
                }

                return node;
        }
}

int main(void) {
        //Pointer to root node
        struct node *root = NULL;

        root = insert(root,4);
        root = insert(root,2);
        root = insert(root,3);
        root = insert(root,5);
        root = insert(root,1);
        root = insert(root,7);

        return 0;
}

And the header file:

/*
 * binary_tree.h
 *
 *  Created on: Jul 12, 2014
 *      Author: ccravens
 */

#ifndef BINARY_TREE_H_
#define BINARY_TREE_H_

struct node {
        int x;
        struct node *left;
        struct node *right;
};

#endif /* BINARY_TREE_H_ */

Any tips appreciated, thanks!

Answer 1

This line:

struct node *n = (struct node*)malloc(sizeof(struct node*));

Should be:

struct node *n = (struct node*)malloc(sizeof(struct node));

You are allocating a pointer (8 bytes) rather than a struct node (24 bytes). Problems like this are easy to catch by executing your program under valgrind (www.valgrind.org).