c++ - 无法在 C++ 中找到段错误

Question

我有 3 个 C++ 文件，instrument.h, percussion.h, and instrumentApp.cpp . Instrument.h是基类，percussion.h继承它。 Percussion对象在 instrumentApp.cpp 中定义和实现类(class)。每当我跑instrumentApp.cpp ，我得到了段错误。

我已经设法将错误的原因追溯到重载的 << operator在 percussion.h 中发挥作用我在哪里调用基类的方法 instrument.h .出于某种原因，我的代码无法调用基类的方法，我不知道为什么。你能帮帮我吗？

这是 instrument.h 类

#ifndef INSTRUMENT_H
#define INSTRUMENT_H


class Instrument{
        private:
                std::string name;
                std::string sound;
                std::string lowRange;
                std::string highRange;
        public:
                Instrument(std::string name, std::string sound, std::string lowRange, std::string highRange){
                        this->name = name;
                        this->sound = sound;
                        this->lowRange = lowRange;
                        this->highRange = highRange;
                }

                std::string getName() const{
                        return this->name;
                }

                std::string play()const {
                        return this->sound;
                }

                std::string getLowRange() const{
                        return this->lowRange;
                }

                std::string getHighRange() const{
                        return this->highRange;
                }

                bool isWind();
                bool isWoodWind();
                bool isBrass();
                bool isKeyboard();
                bool isPercussion();
                bool isStrings();

                friend std::ostream &operator <<(std::ostream &os, const Instrument &instrument){
                }
};

#endif

这是 percussion.h 类

#ifndef PERCUSSION_H
#define PERCUSSION_H

#include "instrument.h"

class Percussion : public Instrument{
        private:
                bool struck;
        public:
                Percussion(std::string name, std::string sound, std::string lowRange, std::string highRange, bool struck) : Instrument(name,sound,lowRange,highRange){
                        this->struck=struck;

                }

                bool isStrucked() const {
                        return this->struck;
                }

                bool isPercussion() {
                        return true;
                }

                std::string getType() const{
                        if(this->struck){
                                return "struck";
                        }
                        else{
                                return "";
                        }
                }

                friend std::ostream &operator <<(std::ostream &os,  Percussion &percussion){
           //The error stems from this line of code
          //Apparently, the getName() method in the base class isn't called

                           os<<percussion.getName();

                }

};

#endif

这是实现文件instrumentApp.cpp

 #include <iostream>
 #include <string>
 #include <sstream>
 #include <cstdlib>

 #include "instrument.h"

 #include "percussion.h"
 #include "strings.h"

using namespace std;



int main() {

    Percussion timpani("timpani", "boom", "D2", "A2", true);
    cout << timpani << endl;

    Percussion harp("harp", "pling", "Cb1", "F#7", false);
    cout << harp << endl;

     return 0;
}

Answer 1

这里的问题是当我重载 << 运算符时我没有返回 os 对象。

在percussion.h文件中修复如下

friend std::ostream &operator <<(std::ostream &os,  Percussion &percussion){

        os<<percussion.getName();

        return os;

 }