在 C++ 中,您不能从构造函数调用虚拟/覆盖方法。
现在,您可以这样做是有充分理由的。作为“软件中的最佳实践”,您应该尽可能避免从构造函数调用其他方法,甚至是非虚拟方法。
但是,该规则总是有一个例外,因此您可能希望使用“伪构造函数方法”来模拟它们:
#include <iostream>
class base {
// <constructor>
base() {
// do nothing in purpouse
}
// </constructor>
// <destructor>
~base() {
// do nothing in purpouse
}
// </destructor>
// <fake-constructor>
public virtual void create() {
// move code from static constructor to fake constructor
std::cout << value() << std::endl;
}
// </fake-constructor>
// <fake-destructor>
public virtual void destroy() {
// move code from static destructor to fake destructor
// ...
}
// </fake-destructor>
public virtual const int value() const {
return 0;
}
public virtual void DoSomething() {
// std:cout << "Hello World";
}
};
class derived : public base {
// <fake-constructor>
public override void create() {
// move code from static constructor to fake constructor
std::cout << "Im pretending to be a virtual constructor," << std::endl;
std::cout << "and can call virtual methods" << std::endl;
}
// </fake-constructor>
// <fake-destructor>
public override void destroy() {
// move code from static destructor to fake destructor
std::cout << "Im pretending to be a virtual destructor," << std::endl;
std::cout << "and can call virtual methods" << std::endl;
}
// </fake-destructor>
public virtual const int value() const {
return 1;
}
};
int main(void) {
// call fake virtual constructor in same line, after real constructor
derived* example = new example(); example->create();
// do several stuff with your objects
example->doSomething();
// call fake virtual destructor in same line, before real destructor
example->destroy(); delete example();
}
另外,我建议程序员仅将“struct”用于字段结构,将“class”用于具有字段、方法、构造函数等的结构...