C++ - 函数返回"true",但不会被"if"语句看作true

Question

除了"搜索"函数之外,此程序中的所有内容都有效,该函数根据字是否在二叉搜索树中返回true或false.我在"main"中有一个if语句,告诉用户该单词是否在树中.当我单步执行调试器时,它表示该函数应该返回true,但它会直接跳到"main"中if语句的else部分.为什么是这样？它似乎工作得很好,除非它被if语句"查看".例如,"test.txt"包含单词"This Program Works",每个单词在一行中.我知道它正在将它们添加到树中,因为当我"printAll"这些词出来时......

BinarySearchTree

#include "BinarySearchTree.h"
#include <iostream>
using namespace std;

bool BinarySearchTree::search(string target) {

    if(target == data) {
        return true;
    }
    else if(target < data) {
        if(left == nullptr) {
            return false;
        }
        else {
            left->search(target);
        }
    }
    else if(target > data) {
        if(right == nullptr) {
            return false;
        }
        else {
            right->search(target);
        }
    }
}

主要

#include <fstream>
#include <string>
#include <iostream>
#include <vector>
#include "BinarySearchTree.h"

using namespace std;

int main(int argc, char** argv) {
    //pull in text from a .txt file, one word at a time, add each to the      BinarySearchTree.
    //loop and let the user enter a word, let the user know if the word was in the file or not.  Have the user type 0 to quit.
    cout<<"Search: ";
    string target;
    getline(cin,target);

    while(target != "0") {
    ///////////////////MAIN ISSUE HERE/////////////////////////////////
        if(tree.search(target) == true) {
            cout<<"\""<<target<<"\""<<" found in file."<<endl;
        }

        else {
            cout<<"\""<<target<<"\""<<" not found in file."<<endl;
        }
  ////////////////////////////////////////////////////////////////////
        cout<<"Search: ";
        getline(cin,target);

    }
    //now that the user is content, print all words that were in the text file, in lexicographical order.
    tree.printAll();
    cout<<endl;

    return 0;
}

我知道其他一切都运作良好.

Answer 1

你在这里没有回复任何东西:

    else {
        left->search(target);
    }

它应该是:

    else {
        return left->search(target);
    }

你有同样的错误right->search(target).