Mutate private data of a class though a pointer of a class with the same memory layout

mutate.cpp

// Example program
#include <iostream>
#include <string>


class X
{
int x; //private
int y; // private
 public: 
 void print() const { std::cout << x << "    " << y  << std::endl;}
};

class Z
{
 public:
 int x;
 int y;
};

int main()
{
    X x;
    Z* z;
    z = (Z*)&x;
    z->x = 100;
    z->y = 200;
    
    x.print();
}