class constructor question

[StGuru]

Why that constructor, when I got other unparamterized?

Why in this code when I pass by value, there isnt invoking of the constructor of class B?

#include <iostream>
using namespace std;
class B
{
public:
B()
   {
      cout<<"test";
      }
int n;
};
class test
{
private:
int y;
public:
int z;
    test()
    {
    y=1;
    }
     test(B object)
      {
      y=object.n;
      }  
void print_y();   
};

void test::print_y()
{
      cout<<y<<endl;
}
int main()
{
    B ob2;
    B ob3;
    cout<<"Put whatever you want";
    cin>>ob2.n;
    test ob1(ob2);
    
    ob1.print_y();
    
    system("PAUSE");
    
}