这是输出：
ConstructorDestructor constructor with 1 int.
ConstructorDestructor constructor with 2 ints.
ConstructorDestructor constructor with 3 ints.
所有构造函数完成后，完全初始化的构造函数将立即创建对象。 DerivedContainer(int int1) 成功，但是 DerivedContainer(int int1, int int2) 失败，并调用析构函数。
class ConstructorDestructor {
public:
ConstructorDestructor() {
cout << "ConstructorDestructor default constructor." << endl;
}
ConstructorDestructor(int int1) {
cout << "ConstructorDestructor constructor with 1 int." << endl;
}
ConstructorDestructor(int int1, int int2) : ConstructorDestructor(int1) {
cout << "ConstructorDestructor constructor with 2 ints." << endl;
throw exception();
}
ConstructorDestructor(int int1, int int2, int int3) : ConstructorDestructor(int1, int2) {
cout << "ConstructorDestructor constructor with 3 ints." << endl;
}
~ConstructorDestructor() {
cout << "ConstructorDestructor destructor." << endl;
}
};
int main() {
try {
ConstructorDestructor cd{ 1, 2, 3 };
}
catch (const exception& ex){
}
}
输出：
ConstructorDestructor constructor with 1 int.
ConstructorDestructor constructor with 2 ints.
ConstructorDestructor destructor.
继承构造函数 (C++11)
派生类可以使用 using 声明从直接基类继承构造函数，如下面的示例所示：
#include <iostream>
using namespace std;
class Base
{
public:
Base() { cout << "Base()" << endl; }
Base(const Base& other) { cout << "Base(Base&)" << endl; }
explicit Base(int i) : num(i) { cout << "Base(int)" << endl; }
explicit Base(char c) : letter(c) { cout << "Base(char)" << endl; }
private:
int num;
char letter;
};
class Derived : Base
{
public:
// Inherit all constructors from Base
using Base::Base;
private:
// Can't initialize newMember from Base constructors.
int newMember{ 0 };
};
int main(int argc, char argv[])
{
cout << "Derived d1(5) calls: ";
Derived d1(5);
cout << "Derived d1('c') calls: ";
Derived d2('c');
cout << "Derived d3 = d2 calls: " ;
Derived d3 = d2;
cout << "Derived d4 calls: ";
Derived d4;
// Keep console open in debug mode:
cout << endl << "Press Enter to exit.";
char in[1];
cin.getline(in, 1);
return 0;
}
输出：
Derived d1(5) calls: Base(int)
Derived d1('c') calls: Base(char)
Derived d3 = d2 calls: Base(Base&)
Derived d4 calls: Base()
Press Enter to exit.
