为什么这段代码“没有歧义！” - 虚拟功能

Question

为什么下面的代码没有歧义以及它是如何正常工作的？

#include <QCoreApplication>
#include <iostream>
using namespace std;

class Shape{
public:
    virtual void drawShape(){
        cout << "this is base class and virtual function\n";
    }
};

class Line : public Shape{
public:
    virtual void drawShape(){
        cout << "I am a line\n";
    }
};

class Circle : public Shape{
public:
    virtual void drawShape(){
        cout <<" I am circle\n";
    }
};

class Child : public Line, public Circle{
public:
    virtual void drawShape(){
        cout << "I am child :)\n";
    }
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    //Shape *s;
    //Line l;
    Child ch;
    //s = &l;
    //s = &ch;
    ch.drawShape(); // this is ambiguous right? but it executes properly!
    //s->drawShape();
    return a.exec();
}

Answer 1

这不是模棱两可的，因为Child 定义了它自己对drawShape 的覆盖，ch.drawShape 将调用该函数。如果Child 没有提供对drawShape 的覆盖，则调用将不明确。