#include 
     
      using namespace std;class A {public:    A() { a = 0; }//普通    A(const A&other) {
   //复制        this->a = other.a;    }    A &operator=(const A & other) {
   //赋值        this->a = other.a;        return *this;    }A(double convert) {
   //转换构造函数    this->a = int(convert);}private:    int a;};int main(){    A a, b;//调用普通构造函数    A c = b;//调用复制构造函数    c = a;//调用赋值构造函数    A d(c);//调用赋值构造函数double e = 0.1;A f(e);    return 0;}