Which of the following statement is correct about the program given below?

#include<iostream.h> 
class AptitudeData
{
    int x, y, z; 
    public:
    AptitudeData(int xx, int yy, int zz)
    {
        x = ++xx;
        y = ++yy;
        z = ++zz;
    }
    void Show()
    {
        cout<< '' << x++ << ' ' << y++ << ' ' << z++;
    } 
}; 
int main()
{
    AptitudeData objData(1, 2, 3);
    objData.Show();
    return 0; 
}