Binary tree problem

I've been trying to code my own binary tree (without looking at any examples), but for some reason my code just refuses to compile! here is my source:

Code:

#include <iostream.h>

struct node
	{
	node *right;
	node *left;
	int key;
	};
typedef node* NodePtr;

void add_node(NodePtr &tree, int value, int switch);
	
main()
	{
	int num, num_of_nodes;
	NodePtr root, pointer; int called = 0;

	cout << "How many numbers do you whish to add to the tree?";
	cin >> num_of_nodes;
	cout << "Enter the first node:";
	cin >> num;
	root->key = num;
	pointer = root;
	for (int i = 0; i < num_of_nodes; i++)
		{
		cout << "Enter a number to add:";
		cin >> num;
		add_node(pointer, num, called);
		pointer = root;
		called = 0;
		} 
	
	return 0;
	}
void add_node(NodePtr &tree, int value, int switch)
	{
	if (switch == 0)
		{
		node* tmp = new node;   
		tmp->key = value;  
		switch = 1;  
		}
	if (value >= tree->key)    
	    if (tree->right != NULL)
		{
		tree = tree->right;
		add_node(tree, value);
		}
	    else
		tree->right = tmp;

	if (value <= tree->key)    
	    if (tree->left != NULL)
		{
		tree = tree->left;
		add_node(tree, value);
		}
	    else
		tree->left = tmp;
			
	}

It all seems to check out fine, yet I get the following errors from g++:

Code:

binary_tree.cpp:11: parse error before `switch'
binary_tree.cpp:35: parse error before `switch'
binary_tree.cpp: In function `void add_node(...)':
binary_tree.cpp:37: parse error before `switch'
binary_tree.cpp:40: `tmp' undeclared (first use this function)
binary_tree.cpp:40: (Each undeclared identifier is reported only once for each
   function it appears in.)
binary_tree.cpp:40: `value' undeclared (first use this function)
binary_tree.cpp:41: parse error before `=' token
binary_tree.cpp: At global scope:
binary_tree.cpp:47: `tree' was not declared in this scope
binary_tree.cpp:47: ISO C++ forbids declaration of `add_node' with no type
binary_tree.cpp:47: `int add_node' redeclared as different kind of symbol
binary_tree.cpp:36: previous declaration of `void add_node(...)'
binary_tree.cpp:47: initializer list being treated as compound expression
binary_tree.cpp:48: parse error before `}' token
binary_tree.cpp:56: `tree' was not declared in this scope
binary_tree.cpp:56: ISO C++ forbids declaration of `add_node' with no type
binary_tree.cpp:56: redefinition of `int add_node'
binary_tree.cpp:47: `int add_node' previously defined here
binary_tree.cpp:56: initializer list being treated as compound expression
binary_tree.cpp:57: parse error before `}' token

WHY!?

switch is a reserved keyword. That's like naming a variable if or else or return.

Originally posted by jdinger
switch is a reserved keyword. That's like naming a variable if or else or return.

Silly me. I just wasn't paying attention!

i'm not sure what tmp should be declared as so u have to fix that. Your add_node function takes 3 params, u only had the first two so i NULL'd the third, declare tmp and it should work i think.

Code:

#include <iostream.h>

struct node
	{
	node *right;
	node *left;
	int key;
	};
typedef node* NodePtr;

void add_node(NodePtr &tree, int value, int switch1);
	
main()
	{
	int num, num_of_nodes;
	NodePtr root, pointer; int called = 0;

	cout << "How many numbers do you whish to add to the tree?";
	cin >> num_of_nodes;
	cout << "Enter the first node:";
	cin >> num;
	root->key = num;
	pointer = root;
	for (int i = 0; i < num_of_nodes; i++)
		{
		cout << "Enter a number to add:";
		cin >> num;
		add_node(pointer, num, called);
		pointer = root;
		called = 0;
		} 
	
	return 0;
	}
void add_node(NodePtr &tree, int value, int switch1)
	{
	if (switch1 == 0)
		{
		node* tmp = new node;   
		tmp->key = value;  
		switch1 = 1;  
		}
	if (value >= tree->key)    
	    if (tree->right != NULL)
		{
		tree = tree->right;
		add_node(tree, value, NULL);
		}
	    else
		tree->right = tmp;

	if (value <= tree->key)    
	    if (tree->left != NULL)
		{
		tree = tree->left;
		add_node(tree, value,NULL);
		}
	    else
		tree->left = tmp;
			
	}

Ok... I got the following program worked out... works nicely too, IMHO.

Code:

#include <iostream>
using namespace std;

struct node
	{
	node *right;
	node *left;
	int key;
	};
typedef node* NodePtr;

void add_node(NodePtr &tree, NodePtr &tmp);

void print_inorder(NodePtr p) 
	{
    	if (p != NULL) 
		{
       		print_inorder(p->left);  // print left subtree
        	                cout << p->key << endl; // print this node
        	                print_inorder(p->right); // print right subtree
    		}
	}
	
main()
	{
	int num, num_of_nodes;
	NodePtr root, pointer; 

	root = new node;
	pointer = new node;

	cout << "How many numbers do you whish to add to the tree?";
	cin >> num_of_nodes;

	cout << "Enter the first node:";
	cin >> num;
	root->key = num;
	pointer = root;
	for (int i = 0; i < num_of_nodes-1; i++)
		{
		cout << "Enter a number to add:";
		cin >> num;
		node* tmp = new node;   
		tmp->key = num; 
		add_node(pointer, tmp);
		pointer = root;
		} 
	cout << "The numbers entered in order is:" << endl;
	print_inorder(root);
	return 0;
	}
void add_node(NodePtr &tree, NodePtr &tmp)
	{ 

	if (tmp->key >= tree->key)    
	    if (tree->right != NULL)
		{
		tree = tree->right;
		add_node(tree, tmp);
		}
	    else
		tree->right = tmp;

	if (tmp->key <= tree->key)    
	    if (tree->left != NULL)
		{
		tree = tree->left;
		add_node(tree, tmp);
		}
	    else
		tree->left = tmp;
			
	}

Please telll me if there are some things I can improve on in this!

EDIT: oh.. as for tmp, I decided it only needed to be declared once, so I left it out of the function. The print function prints the numbers out in a sorted fashion, and I've tested a modification using a random number generator. For some odd reason, whenever I use 5 or more nodes, it hangs. Maybe its the way I use random numbers, but it couldbe that I have too many things running. Let me know if anyone has any ideas, and could point out other things I coudl do with this program.