C++的构造和析构顺序

子类的构造和析构过程, 上代码:

#include <iostream>

using namespace std;

class CA {
public:
CA() { cout << "CA()" << endl; }
~CA() { cout << "~CA()" << endl; }
};

class CB : public CA {
public:
CB() { cout << "CB()" << endl; }
~CB() { cout << "~CB()" << endl; }
};

int main() {
cout << "Hello, World!" << endl;
CB b;

return 0;
}

输出:

Hello, World!

CA()

CB()

~CB()

~CA()

总结:

子类构造顺序:父类构造->子类有构造

子类析构顺序:子类析构->父类析构

孙子类的构造和析构过程, 上代码:

#include <iostream>

using namespace std;

class CA {
public:
CA() { cout << "CA()" << endl; }
~CA() { cout << "~CA()" << endl; }
};

class CB : public CA {
public:
CB() { cout << "CB()" << endl; }
~CB() { cout << "~CB()" << endl; }
};

class CC : public CB {
public:
CC() { cout << "CC()" << endl; }
~CC() { cout << "~CC()" << endl; }
};

int main() {
cout << "Hello, World!" << endl;
//CB b;
CC c;

return 0;
}

输出:

Hello, World!

CA()

CB()

CC()

~CC()

~CB()

~CA()

总结:

孙子类的构造过程: 爷类构造->父类构造-孙子类构造

孙子类的析构过程: 孙子类析构->父类析构->爷类析构