class constructor question

[StGuru]

I got this code:

#include <iostream>
using namespace std;

class test
{
private:
int y;
public:
int z;
     test(test object)
      {
      y=object.z;
      }  
void print_y();   
};

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

I got dozens of errors like "You should use const test &". I think everything is correct with the code. why i got those errors?

Thanks in advance.

Regards.