Getting started with classes (2): Digital box

// Class unit numbox; interfacetype tnumbox = class private fcount: integer; public procedure addone; Procedure addfive; Procedure zerocount; function getcount: integer; end; implementation {tnumbox} procedure tnumbox. addone; begin Inc (fcount); end; Procedure tnumbox. addfive; begin Inc (fcount, 5); end; Procedure tnumbox. zerocount; begin fcount: = 0; end; function tnumbox. getcount: integer; begin result: = fcount; end.
  
   
 // Call unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1 = Class (tform) button1: tbutton; button2: tbutton; button3: tbutton; Procedure upload (Sender: tobject); Procedure button1click (Sender: tobject); Procedure upload (Sender: tobject); Procedure button3click (Sender: tobject ); procedure formdestroy (Sender: tobject); Private {private Declarations} public {public declarations} end; var form1: tform1; implementation {$ R *. DFM} uses numbox; var numbox1: tnumbox; Procedure tform1.formcreate (Sender: tobject); begin numbox1: = tnumbox. create; end; Procedure extract (Sender: tobject); begin numbox1.addone; text: = inttostr (numbox1.getcount); end; Procedure extract (Sender: tobject); begin numbox1.addfive; text: = inttostr (numbox1.getcount); end; Procedure success (Sender: tobject); begin success; text: = inttostr (numbox1.getcount); end; Procedure success (Sender: tobject); begin numbox1.free; end; end.