(7)-构造函数在类继承时
最后更新于:2022-04-01 16:11:08
**代码**:
~~~
#include <iostream>
using namespace std;
class A
{
public:
A()
{
Print();
}
virtual void Print()
{
cout<<"A is constructed.\n";
}
};
class B: public A
{
public:
B()
{
Print();
}
virtual void Print()
{
cout<<"B is constructed.\n";
}
};
int main()
{
A* pA = new B();
delete pA;
return 0;
}
~~~
(感谢网友提供的题目)
**疑**:以上代码输出结果是?
输出结果如下:
A is constructed.
B is constructed.
解释:当new B()时,因为B继承了A,所以编译器首先调用A的构造函数,A的构造函数里是调用A类里的Print(),所以首先输出A is constructed ,然后调用的是B的构造函数,此时Print虚函数指针已指向B的void print(),所以输出B is constructed。
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