在第一個BST上插入無結果函數errror？

Question

所以我試圖學習如何編寫我的第一個BST，這很難....我只用幾行代碼就遇到了麻煩。問題在插入，但我已經包括了一切，以便我可以得到我的風格/其他錯誤的一些反饋。我被建議使用指針實現的指針，但我們還沒有學到它，所以我不覺得舒適/知道如何編寫它。在

誤差

cc1plus: warnings being treated as errors 
tree.cpp: In member function âbool Tree::insert(Tree::Node*&, int, std::string)â: 
tree.cpp:34: warning: control reaches end of non-void function 

的tree.h中文件

#ifndef TREE_H 
#define TREE_H 

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

class Tree 
{ 
public: 
    Tree(); 
    bool insert(int k, string s); 

private: 
    struct Node 
    { 
    int key; 
    string data; 
    Node* left; 
    Node* right; 
    }; 
    Node* root; 
    bool insert(Node*& root, int k, string s); 
}; 

#endif 

tree.cpp

#include <iostream> 
#include "tree.h" 
#include <stack> 
#include <queue> 
#include <string> 
using namespace std; 

Tree::Tree() 
{ 
    root = NULL; 
} 

bool Tree::insert(int k, string s) 
{ 
    return insert(root, k, s); 
} 

bool Tree::insert(Node*& currentRoot, int k, string s) 
{ 
    if(currentRoot == NULL){ 
    currentRoot = new Node; 
    currentRoot->key = k; 
    currentRoot->data = s; 
    currentRoot->left = NULL; 
    currentRoot->right = NULL; 
    return true; 
    } 
    else if (currentRoot->key == k) 
    return false; 
    else if (currentRoot->key > k) 
    insert(currentRoot->left, k, s); 
    else 
    insert (currentRoot->right,k, s); 
} 

movieList.cpp

#include <iostream> 
#include <stack> 
#include <queue> 
#include <string> 
#include "tree.h" 


using namespace std; 

int main() 
{ 
    Tree test; 
    test.insert(100, "blah"); 
    return 0; 
} 

Answer 1

cc1plus: warnings being treated as errors 
tree.cpp: In member function âbool Tree::insert(Tree::Node*&, int, std::string)â: 
tree.cpp:34: warning: control reaches end of non-void function 

這只是說你不會在每一個可能的路徑上返回一些東西。試試這個：

bool Tree::insert(Node*& currentRoot, int k, string s) 
{ 
    if(currentRoot == NULL){ 
    currentRoot = new Node; 
    currentRoot->key = k; 
    currentRoot->data = s; 
    currentRoot->left = NULL; 
    currentRoot->right = NULL; 
    return true; 
    } 
    else if (currentRoot->key == k) 
    return false; 
    else if (currentRoot->key > k) 
    return insert(currentRoot->left, k, s); 
// ^^^^^^ 
    else 
    return insert (currentRoot->right,k, s); 
// ^^^^^^ 
} 

Answer 2

如何：

bool Tree::insert(Node*& currentRoot, int k, string s) 
{ 
    if(currentRoot == NULL){ 
    currentRoot = new Node; 
    currentRoot->key = k; 
    currentRoot->data = s; 
    currentRoot->left = NULL; 
    currentRoot->right = NULL; 
    return true; 
    } 
    else if (currentRoot->key == k) 
    return false; 
    else if (currentRoot->key > k) 
    insert(currentRoot->left, k, s); 
    else 
    insert (currentRoot->right,k, s); 
    return true; 
} 

所有部門需要返回一個值（布爾在這種情況下）。