Question

Having code issues wth my C++ program. My program checks if two binary trees are similar and if they're not they return false. My program is return true with different binary trees. Could use some help thanks

#include <iostream>
#include <string>
using namespace std;

//Struct of Nodes
struct BinarySearchTree
{
int data;
BinarySearchTree *left;
BinarySearchTree *right;
};

// Inserting nodes into BST
BinarySearchTree* insert( BinarySearchTree* node, int val) {
if (node == NULL) {
BinarySearchTree *newNode = new BinarySearchTree();
newNode->data = val;
newNode->left = newNode->right = NULL;
return newNode;
}
  
else if (val < node->data){
node->left = insert(node->left, val);
}
else if (val > node->data) {
node->right = insert(node->right, val);
}
return node;
}

bool isSimilar(struct BinarySearchTree *node, struct BinarySearchTree *node1)
{
if(node ==NULL && node1 == NULL) {
return true;
}
  
if(node!=NULL && node1!=NULL) {
if(node->data == node1->data &&
isSimilar(node->left, node1->left) && isSimilar(node->right, node1->right)) {
return true;
}
}
  
else {
return false;
}
  
}
  
  
  
  

int main() {
//Local variables
int n, n2;
int node;
std::string prompt;
  
//Intializing the root
BinarySearchTree *root = NULL;
BinarySearchTree *root2 = NULL;
  
  
start:
  
//User input
std::cout<<"Enter the amount of nodes you want to add to the first BST: ";
std::cin>>n;
  
//Intializing the root of the tree
root = insert(root, 5);
root2 = insert(root, 5);
  

//Inserting Values into the BST
for(int i=0; i<n; i++)
{
std::cout<<"Enter the "<<i+1<<" node: ";
cin>>node;
insert(root, node);
}
  
  
std::cout<<"Enter the amount of nodes you want to add to the second BST: ";
std::cin>>n2;
  
for(int i=0; i<n2; i++)
{
std::cout<<"Enter the "<<i+1<<" node: ";
cin>>node;
insert(root2, node);
}
  
  
if(isSimilar(root, root2))
{
std::cout<<"Binary trees are similar"<<std::endl;
}
  
else
{
std::cout<<"Binary trees are not similar"<<std::endl;
}
  
std::cout<<"Would you like to try again? Type Y or N: ";
std::cin>>prompt;
  
prompt = toupper(prompt[0]);
  
if(prompt == "Y")
{
goto start;
}

  
return 0;
}

Answer 1

You have done a single mistake in the above code and that is in line 70(including empty lines) where you have initialized the roots of the tree in the second initialization you have passed the root of first tree which was the reason for the wrong output.

code :

root = insert(root, 5);
root2 = insert(root, 5);

Right answer is :

root = insert(root, 5);
root2 = insert(root2, 5); //you have to pass the root of that tree only instead of passing the root of another tree

Output :