Still can't find largest number in binary tree - c++

Question

I still can't find the largest number in my tree, but now I am really not complicating it, I think it should work, there is no error, but it just won't show me in the console. Anyone got an idea? I am getting really frustrated.
Here is my entire code:
#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
template<class T>
class BinaryTree
{
struct Node
{
T data;
Node* lChildptr;
Node* rChildptr;
Node(T dataNew)
{
data = dataNew;
lChildptr = NULL;
rChildptr = NULL;
}
};
private:
Node* root;
void Insert(T newData, Node* &theRoot)
{
if(theRoot == NULL)
{
theRoot = new Node(newData);
return;
}
if(newData < theRoot->data)
Insert(newData, theRoot->lChildptr);
else
Insert(newData, theRoot->rChildptr);;
}
void PrintTree(Node* theRoot)
{
if(theRoot != NULL)
{
PrintTree(theRoot->lChildptr);
cout<< theRoot->data<<" \n";;
PrintTree(theRoot->rChildptr);
}
}
T Largest( Node* theRoot)
{
if ( root == NULL ){
cout<<"There is no tree";
return -1;
}
if (theRoot->rChildptr != NULL)
return Largest(theRoot->rChildptr);
else
return theRoot->data;
cout<<theRoot->data;
};
public:
BinaryTree()
{
root = NULL;
}
void AddItem(T newData)
{
Insert(newData, root);
}
void PrintTree()
{
PrintTree(root);
}
T Largest()
{
return Largest(root);
}
};
int main()
{
BinaryTree<int> *myBT = new BinaryTree<int>();
myBT->AddItem(2);
myBT->AddItem(5);
myBT->AddItem(1);
myBT->AddItem(10);
myBT->AddItem(15);
myBT->PrintTree();
myBT->Largest();
}
and here is the part that is supposed to find the largest number (the child that is far right down):
T Largest( Node* theRoot)
{
if ( root == NULL ){
cout<<"There is no tree";
return -1;
}
if (theRoot->rChildptr != NULL)
return Largest(theRoot->rChildptr);
else
return theRoot->data;
cout<<theRoot->data;
};

Answer 1

There are two problems in your code in Largest():
It looks like you wanted to execute two statements in the else clause, but you didn't use braces.
You wanted to execute the cout print after returning, which is impossible. Switch the order around.
So you should replace your fragment of code with this:
else {
cout << theRoot->data;
return theRoot->data;
}
Incidentally, don't let double semicolons (;;) stay in your code. It's harmless in most cases, but it's always bad style.

Answer 2

Here's a fixed and slightly cleaned-up version that works:
#include <iostream>
#include <string>
#include <cstdlib>
using namespace std;
template<class T>
class BinaryTree
{
struct Node
{
T data;
Node* lChildptr;
Node* rChildptr;
Node(T dataNew)
{
data = dataNew;
lChildptr = 0;
rChildptr = 0;
}
};
private:
Node* root;
void Insert(T newData, Node** theRoot)
{
if (*theRoot == 0)
{
*theRoot = new Node(newData);
}
else if (newData < (*theRoot)->data)
Insert(newData, &((*theRoot)->lChildptr));
else
Insert(newData, &((*theRoot)->rChildptr));
}
void PrintTree(Node* theRoot)
{
if (theRoot != 0)
{
PrintTree(theRoot->lChildptr);
cout << theRoot->data << " " << endl;
PrintTree(theRoot->rChildptr);
}
}
T Largest(Node* theRoot)
{
if (root == 0)
{
throw "There is no tree";
}
if (theRoot->rChildptr != 0)
return Largest(theRoot->rChildptr);
else
return theRoot->data;
}
public:
BinaryTree()
{
root = 0;
}
void AddItem(T newData)
{
Insert(newData, &root);
}
void PrintTree()
{
PrintTree(root);
}
T Largest()
{
return Largest(root);
}
};
int main()
{
BinaryTree<int> *myBT = new BinaryTree<int>();
cout << "The tree is empty. Trying to find the largest element." << endl;
try
{
cout << "Largest element: " << myBT->Largest() << endl;
}
catch (const char* e)
{
cout << "Exception caught: " << e << endl;
}
myBT->AddItem(15);
myBT->AddItem(2);
myBT->AddItem(5);
myBT->AddItem(1);
myBT->AddItem(10);
cout << "Tree:" << endl;
myBT->PrintTree();
cout << "Largest element: " << myBT->Largest() << endl;
}
Output:
The tree is empty. Trying to find the largest element.
Exception caught: There is no tree
Tree:
1
2
5
10
15
Largest element: 15