hello can someone try to explain me the steps and the output of this ?

hello can someone try to explain me the steps and the output of this ?

 downTest(& )

{

        -= 2;

}

 function( &, & )

{

       downTest();

        += ;

}

 main() 

{            

        c = ;

       function(a, c);

       cout << c << endl;

       system();

        0;

}