My program goal is to search for a tree node with a given key using depth-first search and if a node with that key is found it will be returned to the caller function. The problem is that accessing the node after DFS execution terminates the program with a segmentation fault, exactly when it searches for a node in the right subtree, but not when searching on the left subtree.

This is the source code:

#include <iostream>

using namespace std;

struct node 
    char data;
    struct node *left;
    struct node *right;
};

struct node *root = nullptr;

struct node* addNewNode(char newData) {
    struct node* newNode = new node;
    newNode->data = newData;
    newNode->left = nullptr;
    newNode->right = nullptr;

    return newNode;
}

struct node* preOrder(struct node *srcNode, char key) {
    if (srcNode != nullptr) {
        if (srcNode->data == key)
            return srcNode;
        return preOrder(srcNode->left, key);
        return preOrder(srcNode->right, key);
    }
}

int main() {
    root = addNewNode('a');
    root->left = addNewNode('e');
    root->right = addNewNode('c');
    root->left->left = addNewNode('h');
    root->left->right = addNewNode('z');

    struct node* res = preOrder(root, 'c');    
    cout << res->data;

    return 0;
}