#include<iostream>
class Foo
{
public:
    Foo(int v) :m_value(v) { } //1
    void print()
    {
        std::cout << m_value;
    }
    ~Foo() {}
    
private:
    Foo() { m_value = 0; }//2
    int m_value;
};
int main()
{
    Foo a;//3
    a.print();
    Foo b(1);//4
    b.print();
}