c++ - 在第一个 BST 上插入非空函数错误的结尾？

Question

所以我正在尝试学习如何编写我的第一个 BST，这很难......我已经遇到了仅仅几行代码的问题。问题出在插页中，但我已经包含了所有内容，以便我可以获得有关我的风格/其他错误的一些反馈。有人建议我使用指向指针实现的指针，但我们还没有学会它，所以我还不放心/不知道如何编写它。

错误是

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

tree.h 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

树.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);
}

电影列表.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

这只是说你不会在每条可能的路径上返回一些东西。试试这个:

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);
//  ^^^^^^
}