c++ - 头文件中没有对构造函数的匹配函数调用调用

Question

我看过类似的问题并尝试了他们的解决方案，但对他们的回答似乎不起作用。我有以下代码:

.h

#include <iostream>
#include <vector>
#include <string>
using std::string; using std::vector;

struct DialogueNode;

struct DialogueOption   {
    string text;
    DialogueNode *next_node;
    int return_code;

    DialogueOption(string t, int rc, DialogueNode * nn) : text{t}, 
        return_code{rc}, next_node{nn}   {}
};

struct DialogueNode {
    string text;
    vector <DialogueOption> dialogue_options;
    DialogueNode();
    DialogueNode(const string &);
};

struct DialogueTree {
    DialogueTree()  {}
    void init();
    void destroyTree();

    int performDialogue();
private:
    vector <DialogueNode*> dialogue_nodes;
};

.cpp

#include "dialogue_tree.h"

DialogueNode::DialogueNode(const string &t) : text{t} {}

void DialogueTree::init()   {
    string s = "Hello";
    for(int i = 0; i < 5; i++)  {
        DialogueNode *node = new DialogueNode(s);
        dialogue_nodes.push_back(node);
        delete node;
    }
}

void DialogueTree::destroyTree()    {

}

int DialogueTree::performDialogue() {
    return 0;
}

int main()  {
    return 0;
}

我得到错误:错误:没有匹配函数调用'DialogueNode::DialogueNode(std::__cxx11::string&)' DialogueNode *node = new DialogueNode(s);

编辑关于错误的附加说明

dialogue_tree.h:17:8: note: candidate: DialogueNode::DialogueNode()
dialogue_tree.h:17:8: note:   candidate expects 0 arguments, 1 provided
dialogue_tree.h:17:8: note: candidate: DialogueNode::DialogueNode(const DialogueNode&)
dialogue_tree.h:17:8: note:   no known conversion for argument 1 from ‘std::__cxx11::string {aka std::__cxx11::basic_string<char>}’ to ‘const DialogueNode&’
dialogue_tree.h:17:8: note: candidate: DialogueNode::DialogueNode(DialogueNode&&)
dialogue_tree.h:17:8: note:   no known conversion for argument 1 from ‘std::__cxx11::string {aka std::__cxx11::basic_string<char>}’ to ‘DialogueNode&&’

这对我来说毫无意义，因为我将构造函数定义为将 string 作为参数。

Answer 1

您已将构造函数声明为:

DialogueNode(const string);

但是定义为:

DialogueNode(const string &t);

这两个不一样；前者采用 const string 而后者采用 const string 引用。您必须添加 & 以指定引用参数:

DialogueNode(const string &);