Find 2nd Key in BST - c++

Question

I posted something yesterday and got some help to get started, and I feel like I am almost there now. I have created a BST, with the primary key as a name, and the secondary key as that persons weight. I have managed to finish everything I need except for searching for the lowest weight (secondary key). My method to search the minimum weight is a preorder traversal, and it outputs all of the weights correctly to the screen. What is the technique to go about for determining which is the lowest now? I've tried a few different if statements, and creating a minwt int, but am having no luck getting to work (I think it has something to do with the recursion). Anyways, here is the code. Any help, like always, is greatly appreciated. Thanks.
#include <iostream>
using namespace std;
class tNode
{
public:
string name;
int wt;
tNode *left, *right;
tNode()
{
left = right = 0;
}
tNode(string name, int wt, tNode *l = 0, tNode *r = 0)
{
this->name = name;
this->wt = wt;
left = l;
right = r;
}
};
class bSTree
{
public:
tNode *root;
bSTree()
{
root = 0;
}
bool add(string name, int wt)
{
tNode *temp = root, *prev = 0;
while (temp != 0)
{
prev = temp;
if (name < temp->name)
{
temp = temp->left;
}
else
{
temp = temp->right;
}
}
if (root == 0)
{
root = new tNode(name, wt);
}
else if (name < prev->name)
{
prev->left = new tNode(name, wt);
}
else if (name > prev->name)
{
prev->right = new tNode(name, wt);
}
else
{
return false;
}
return true;
}
void searchWeight(tNode* temp)
{
// DETERMINE LOWEST WEIGHT CONTAINED IN TREE
if (temp != 0)
{
cout << temp->wt << endl;
searchWeight(temp->left);
searchWeight(temp->right);
}
}
};

Answer 1

You need some temporary variables to hold the lowest weight and associated key. They need to be accessible outside of the scope of your searchWeight() function. For example:
#include <iostream>
using namespace std;
int lowest_weight = 999999; // Something sufficiently high
string lowest_weight_key;
class tNode
{
/*...*/
void searchWeight(tNode* temp)
{
// DETERMINE LOWEST WEIGHT CONTAINED IN TREE
if (temp != 0)
{
// if temp->wt is lower than lowest weight
// set lowest_weight equal to temp->wt
// and set lowest_weight_key equal to temp->name
cout << temp->wt << endl;
searchWeight(temp->left);
searchWeight(temp->right);
}
}
};
Now, just print out the values of lowest_weight and lowest_weight_key after calling searchWeight().