Searching through a BST based on user input C++

I was thinking of implementing a little program using a BST. Which basically moves through the tree and inserts a value based on user input. However the node values are only strings and we branch through based on user input such as for example in this tree:

                                      alpha1                                     /      \                                 alpha 2  alpha 2                                  / \      / \                                 N1  N2    N3 N4      where alpha1 and alpha2 are strings  Nx is NULL pointer and x is a number {1...infinity}    

For example if a user provided a string of "10" and number to replace "66" the program would go to pointer N3 as 1 = tree_right and 0 = tree_left and replace it with the number 66.

Right now I can do this manually as such:

t->right->left = add_tree("66", 0,0);

And my program currently implements the alpha tree above but I have yet to implement the functionality for adding it via subroutines/recursion as this tree could go to alpha10 in depth and I can't manually do it.

This code implements the alpha tree

struct TreeNode{    std::string val;       TreeNode* left;    TREENode* right;  };      TreeNode* add_tree(std::string value, TreeNode* l, TreeNode* r){    TreeNode* tmp;      tmp = new TreeNode;    tmp->val = value;    tmp->left = l;    tmp->right = r;    return tmp;  }    // This makes the alpha tree with the null pointers  TreeNode* insertion_tree(std::string e, TreeNode* t){            if(t == NULL){      return add_tree(e, 0,0);    }      else if(e ==  "alpha"){      t->left = insertion_tree(e, t->left);      t->right = insertion_tree(e, t->right);      return t;    }      else{      return 0;    }    }    

I tried this sort of for-loop but as I keep on re-declaring the pointer it causes the previous tree to be forgotten and it just created a tree with the element I inserted

// This should give me the location of the node I want to replace after traversing e.g:"01"  TreeNode* replace_null(std::string e, TreeNode* t){        for(int i=0;i<e.length();i++){            if(e[i] == "0"){        tmp = tmp->left;      }        if(e[i] == "1"){        tmp = tmp->right;      }          }      return tmp;    }  

It would be a lifesaver if anybody could help me as I've been stuck on replacing the NULL for a couple of hours.

https://stackoverflow.com/questions/66630948/searching-through-a-bst-based-on-user-input-c March 15, 2021 at 08:28AM