Is my binary tree program reaching an overflow/recursive maximum? - recursion

Question

#include <iostream>
using namespace std;
struct Node{
bool flag;
char letter;
Node* left;
Node* right;
};
typedef Node* Nodeptr;
int stop = 0;
void splitString(string sequence, Nodeptr branch){
//cout << sequence << " ";
//cout << sequence.size() << endl;
if(stop == 20) return;
else stop++;
if(sequence.size() == 1){
branch->flag = true;
branch->letter = sequence[0];
}
else{
int half = sequence.size()/2;
Node* left = new Node;
Node* right = new Node;
branch->flag = false;
branch->left = left;
branch->right = right;
splitString(sequence.substr(0, half), left);
splitString(sequence.substr(half), right);
}
return;
}
void print(Nodeptr root){
if(root->flag)
cout << root->letter;
else{
print(root->left);
print(root->right);
}
return;
}
int main() {
std::cout << "Hello World!\n";
Nodeptr tree = new Node;
splitString("Heaven on ", tree);
print(tree);
//the above two lines run fine
Nodeptr tree2 = new Node;
splitString("Heaven on E", tree2); //this code will run fine
//print(tree2); //this code will give me an EXITED, SEGMENTATION FAULT error
}
Considering that the two lines:
splitString("Heaven on ", tree);
print(tree);
run fine, but these do not:
splitString("Heaven on E", tree2);
//print(tree2); //this code will give me an EXITED, SEGMENTATION FAULT error
I come to think that I have reached the maximum recursion depth. I reviewed my code for the building and traversing the binary tree but I cannot find any problems there. What is the reason for the error? Thanks!

Answer 1

For two reason:
you are using a global, which is a very bad practice, and for example in this case you are not resetting it after the first splitString
you are not managing the case where the string has 0 as size, in the right way
This is a possible implementation of splitString which works (without globals):
void splitString(string sequence, Nodeptr branch){
if(sequence.size() == 1){
branch->flag = true;
branch->letter = sequence[0];
}
else if (sequence.size() > 1){
int half = sequence.size()/2;
Node* left = new Node;
Node* right = new Node;
branch->flag = false;
branch->left = left;
branch->right = right;
splitString(sequence.substr(0, half), left);
splitString(sequence.substr(half), right);
}
else {
branch->flag = true;
branch->letter = '\0';
}
}
There is surely a better way to do this, and i'll encourage you to change the data structor in order to makes it happen (for example don't use the flag to mark the leaves of the tree, just check if there is left is been set or is nullptr)