离开作用域时析构函数的调用顺序?(C++)
我正在尝试理解退出作用域时析构函数调用的顺序。假设我有以下代码:
class Parent{
Parent(){cout<<"parent c called
";}
~Parent(){cout<< "parent d called
";}
};
class Child: public parent{
Child(){cout<< "child c called
";}
~Child(){cout<<"child d called
";}
};
现在,我知道子构造函数和析构函数派生自父函数,因此以下主函数:
int main(){
Parent Man;
Child Boy;
return 0;
}
将产生输出:
parent c called
parent c called
child c called
... //Now what?
但现在,当我退出范围时会发生什么?我有多个东西需要销毁,那么编译器如何选择顺序呢?我可能有两种输出可能性:
parent c called | parent c called
parent c called | parent c called
child c called | child c called
child d called | parent d called
parent d called | child d called
parent d called | parent d called
左边的情况适用于男孩首先被摧毁的情况,右边的情况适用于人首先被摧毁的情况。计算机如何决定首先删除哪一个?
解决方案
派生析构函数在祖先析构函数之前调用。因此,将首先调用Child
析构函数体,然后调用Parent
析构函数体。并且构造的对象是以相反的顺序析构的,因此将在析构Man
对象之前析构Boy
对象。
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