【发布时间】：2018-05-08 15:11:40
【问题描述】：
我正在编写一个程序，其中超类“Entry”模拟一个库输入，其中有几个子类。其中之一是musicAlbum。
entry 有一个带有两个字符串参数的构造函数，用于获取借用项目的名称和年份。然后子类 musicAlbum 有一个构造函数来设置几个字符串参数（艺术家和唱片标签）以及在超类中检索的参数。但是我收到一条错误消息，指出超类中没有默认构造函数，所以我相信我做错了一些非常明显但我看不到的错误。
有什么帮助吗？
这是超类：
Class entry {
protected:
int borrowed;
string name, borrowedBy, year;
public:
entry(string cborrowedBy, string cyear) {
borrowed = 1; //Borrowed changes to 1 to indicate that is currenty borrowed
year = cyear;
borrowedBy = cborrowedBy;
};
virtual void entryBorrowed(string fname) {
name = fname;
};
void entryReturned() {
borrowed = 0;
}; // Calling this functions changes int borrowed into 0 to indicate that has been returned
virtual void printDetails() {};
};
这是子类：
class musicAlbum : public entry {
protected:
string artist, recordLabel;
public:
musicAlbum(string cmborrowedBy, string cmyear, string cartist, string crecordLabel){
entry(cmborrowedBy, cmyear);
artist = cartist;
recordLabel = crecordLabel;
}
void entryBorrowed(string fname) {
name = fname;
}
void printDetails() {
cout << "This entry borrowed by: " << borrowedBy << " in " << year
<< endl << endl << "Name: " << name << endl << "Artist: " << artist << endl << "Record Label: " << recordLabel << endl;
};
};
【问题讨论】：
标签： c++ inheritance constructor