C++ Constructor delegation

#include <iostream>

class A
{
    int x, y, z;

public:
    A()
    {
        this->x = 0;
        this->y = 0;
        this->z = 0;
    }

    A(int xx) : A()
    {
        this->x = xx;
    }

    A(int xx, int yy) : A(xx)
    {
        this->y = yy;
    }

    A(int xx, int yy, int zz) : A(xx, yy)
    {
        this->z = zz;
    }

    void show()
    {
        std::cout << "x: " << this->x << std::endl;
        std::cout << "y: " << this->y << std::endl;
        std::cout << "z: " << this->z << std::endl << std::endl;
    }
};

int main()
{
    A test;
    test.show();

    A test2(1);
    test2.show();

    A test3(1, 2);
    test3.show();

    A test4(1, 2, 3);
    test4.show();

    return 0;
}