#include <iostream>
class Base
{
public:
Base() {
std::cout << "Base Constructor()" << std::endl;
}
~Base() {
std::cout << "Base Destructor()" << std::endl;
}
};
class Derived : public Base
{
public:
Derived() {
std::cout << "Derived Constructor()" << std::endl;
}
~Derived() {
std::cout << "Derived Destructor()" << std::endl;
}
};
int main()
{
Base *pBase = new Derived;
delete pBase;
}
$ g++ a.cpp && ./a.out
Base Constructor()
Derived Constructor()
Base Destructor()
可以看到，派生类的析构函数没有被调到。
解决方法是，在基类的析构函数前加virtual。
#include <iostream>
class Base
{
public:
Base() {
std::cout << "Base Constructor()" << std::endl;
}
virtual ~Base() {
std::cout << "Base Destructor()" << std::endl;
}
};
class Derived : public Base
{
public:
Derived() {
std::cout << "Derived Constructor()" << std::endl;
}
~Derived() {
std::cout << "Derived Destructor()" << std::endl;
}
};
int main()
{
Base *pBase = new Derived;
delete pBase;
}
$ g++ a.cpp && ./a.out
Base Constructor()
Derived Constructor()
Derived Destructor()
Base Destructor()
