calling by reference a variable which was called by reference by another function without using global var
===

I don't get this part. How can I do it if I'm not allowed to use global variables? Example:

    main()
    { int z;
      function1(&z);
    }
    
    function1(int *x)
    {
      function2(&x);
    }
    
    function2(int *number)
    {
       ++(*number);
    }