Binary Tree (insert and search within radius) - c++

Question

I am writing a binary tree search program but I'm not sure how to add nodes and search through them. The nodes come from a .txt file that is being read with a different file so just assume that already works.
The text file looks like:
Name Location
Old Building 31.2222
New Building 21.2111
Like I said, the program already reads in the file so that's not an issue. However, I have to insert the name and location into the nodes of the binary tree. Then I have to search everything within a range which is where the plus minus comes from.
Side note: my copy constructor may be incorrect as well though it complies properly.
Thanks for the help!
#ifndef BINTREE_HPP
#define BINTREE_HPP
#include <utility>
#include <string>
#include <vector>
class bintree {
// A binary search tree for locations in Lineland.
// Notes:
// - Assume a flat, one-dimensional world with locations from -180 to 180.
// - All locations and distances are measured in the same units (degrees).
public:
// Default constructor
bintree() {
this->root = NULL;
}
// Copy constructor
bintree(const bintree &t) {
this -> root = NULL;
*this = t;
}
// Destructor
~bintree() {
}
// Copy assignment is implemented using the copy-swap idiom
friend void swap(bintree &t1, bintree &t2) {
using std::swap;
// Swap all data members here, e.g.,
// swap(t1.foo, t2.foo);
// Pointers should be swapped -- but not the things they point to.
}
bintree &operator= (bintree other) {
// You don't need to modify this function.
swap(*this, other);
return *this;
}
void insert(const std::string& name, double p) {
// insert node with name and location (p)
}
void within_radius(double p, double r, std::vector<std::string> &result) const {
// Search for elements within the range `p` plus or minus `r`.
// Clears `result` and puts the elements in `result`.
// Postcondition: `result` contains all (and only) elements of the
// tree, in any order, that lie within the range `p` plus or minus
// `r`.
}
private:
struct node
{
node *left;
node *right;
};
node* root;
};
#endif

Answer 1

First, your nodes need to hold the data:
struct node
{
node *left;
node *right;
std::string name; // This is the key for your reasearch
double p; // followed by other data
};
Then you can think to browsing through your tree to insert a new node.
In this example, I assume that you can insert several nodes with the same name.
void insert(const std::string& name, double p) {
node *n = new node; // create a new node
n->name=name; n->p=p; // intialise the data payload
n->left=n->right=nullptr; // and make it a leaf.
if (root==nullptr) // if tree is empty,
root = n; // add the new node.
else { // else find where to insert it
node* t=root;
while (true) {
if (t->name > n->name) { // go to left
if (t->left==nullptr) {
t->left = n;
break;
}
else t=t->left;
}
else if (t->name == n->name) { // insert between current and next
n->right = t->right;
t->right = n;
break;
}
else { // go to right
if (t->right==nullptr) {
t->right = n;
break;
}
else t=t->right;
}
}
}
}
Here a live demo.
Note that I have only answered your insertion question, you still have to do a lot on your own (operator= and copy constructor need review, a destructor needs to be created, etc...)