我正在尝试将一些歌曲添加到类内的向量中。我存储的一个值是代表歌曲的int。它本质上是一个计数器。我添加的第一首歌曲的值应该是1，第二首应该是2，依此类推。但它得到了其他奇怪的值，比如大随机数（正数和负数）。我无法理解我做错了什么。这是代码：

#include <iostream>
#include <vector>
#include <string>
using namespace std;
class Jukebox{
public:
  void addSong(string artist, string title, string filename) {
    song s {++songCounter, artist, title, filename};
    Songs.push_back(s);
  }
  void printSong (int song) {
    cout << Songs[song].no << ". ";
    cout << Songs[song].artist << " - ";
    cout << Songs[song].title << " : ";
    cout << Songs[song].filename << endl;
  }
private:
  struct song {
    int no;
    string artist;
    string title;
    string filename;
  };
  vector<song> Songs;
  int songCounter;
};
int main() {
  Jukebox jbox;
  jbox.addSong("U2", "Magnificent", "U2-Magnificent.mp3");
  jbox.addSong("Sting", "Englishman in New York", "Sting-Englishman_in_New_York.mp3");
  jbox.addSong("U2", "One", "U2-One.mp3");
  jbox.printSong(0);
  jbox.printSong(1);
  jbox.printSong(2);
  return 0;
}

更新

好吧，我可能很笨，在尝试实现这个之前应该多读一些关于类的内容。但我想我确实读过了，但我仍然不明白。这就是我的课现在的样子（不起作用）：

class Jukebox(): songCounter(0)
 {
public:
  void addSong(string artist, string title, string filename) {
    songCounter++;
    song s {songCounter, artist, title, filename};
    Songs.push_back(s);
  }
  void printSong (int song) {
    cout << Songs[song].no << ". ";
    cout << Songs[song].artist << " - ";
    cout << Songs[song].title << " : ";
    cout << Songs[song].filename << endl;
  }
private:
  int songCounter;
  struct song {
    int no;
    string artist;
    string title;
    string filename;
  };
  vector<song> Songs;
};

最后一句话

好的。从我看到的c++构造函数类的例子中，我对它们的工作方式有一些错误的印象。现在我觉得我得到了更多。但语法对我来说仍然很奇怪。但我试着读得更多，这样我才能真正理解它。以下是我所做的，似乎是有效的：

#include <iostream>
#include <vector>
#include <string>
using namespace std;
class Jukebox {
public:
  void addSong(string artist, string title, string filename) {
    songCounter++;
    song s {songCounter, artist, title, filename};
    Songs.push_back(s);
  }
  void printSong (int song) {
    cout << Songs[song].no << ". ";
    cout << Songs[song].artist << " - ";
    cout << Songs[song].title << " : ";
    cout << Songs[song].filename << endl;
  }
  Jukebox(): songCounter(0) {} // Constructor
private:
  int songCounter;
  struct song {
    int no;
    string artist;
    string title;
    string filename;
  };
  vector<song> Songs;
};
int main() {
  Jukebox jbox;
  jbox.addSong("U2", "Magnificent", "U2-Magnificent.mp3");
  jbox.addSong("Sting", "Englishman in New York", "Sting-Englishman_in_New_York.mp3");
  jbox.addSong("U2", "One", "U2-One.mp3");
  jbox.printSong(0);
  jbox.printSong(1);
  jbox.printSong(2);
  return 0;
}