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// Return the four conditions of the integer const A = 1.8; B =-1.8; begin {returns the smallest integer with a large ratio:} showmessage (inttostr (Ceil (1.8) + ', '+ inttostr (Ceil (-1.8); {return: 2,-1} {return the largest integer with a small

Tstream is an abstract base class and cannot directly generate objects. In a specific application, it mainly uses its child classes: Tfilestream: file stream Tstringstream: String stream Tmemorystream: memory stream Tresourcestream: resource file

1. txmldocument is applicable to operations in memory and creation of new xml2. A txmldocument is actually a node set. 3. Each node includes the name, text content, attribute set, and subnode set. 4. You can location or name: Access Node 5. Each

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, xmldom, xmlintf, msxmldom, xmldoc, stdctrls; Type tform1 = Class (tform) xmldocument1: txmldocument; identifier: tmemo; button1: tbutton;

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, xmldom, xmlintf, msxmldom, xmldoc, stdctrls; Type tform1 = Class (tform) xmldocument1: txmldocument; button1: tbutton; button2: tbutton;

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, xmldom, xmlintf, msxmldom, xmldoc, stdctrls; Type tform1 = Class (tform) xmldocument1: txmldocument; button1: tbutton; Procedure formcreate

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, xmldom, xmlintf, msxmldom, xmldoc, stdctrls; Type tform1 = Class (tform) xmldocument1: txmldocument; button1: tbutton; Procedure formcreate

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls, xmldom, xmlintf, msxmldom, xmldoc; Type tform1 = Class (tform) button1: tbutton; button2: tbutton; button3: tbutton; Procedure

Type trec1 = Record Name: String [12]; age: word; end; trec2 = Record Name: String [12]; age: word; end; var RecA, recb: trec1; recx, recy: trec2; Procedure tform1.button1click (Sender: tobject); begin {assign a value to RecA} RecA. name: = 'zhang

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1 = Class (tform) button1: tbutton; button2: tbutton; button3: tbutton; Procedure button1click (Sender: tobject);

// Point 15: Call a function of another unit // The unit containing the function: Unit unit2; interfacefunction myfun (X, Y: integer): integer; {The function must be declared in the interface area} implementationfunction myfun (X, Y: integer):

// Point 18: if the function is defined in the interface area, you do not need to use forward to declare unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1 = Class

{The following functions have duplicate names, but different parameters. In this case, the overload indicator must be added. During the call, the type and number of parameters are used to determine which one to call. This is an overload .} function

// The standard coverage is such that tbass = Class procedure proc; virtual; {or use dynamic} end; tchild = Class (tbass) Procedure proc; override; end; // The following situations are redefined. For example 3-5, the compilation prompt {Example 1}

What is polymorphism? In my understanding, the same method has different implementations in different objects. Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1

Unit unit1; interfaceuses classes, controls, forms, stdctrls, xmldoc, xmldom, xmlintf, msxmldom; Type tform1 = Class (tform) xmldocument1: txmldocument; memo1: tmemo; button1: tbutton; button2: tbutton; button3: tbutton; button4: tbutton; Procedure

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; Type tform1 = Class (tform) memo1: tmemo; memo2: tmemo; {two memo needs to be added for display} button1: tbutton; Procedure

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls; type {parent class} tbase = Class procedure proc; virtual; abstract; {abstract method} end; {subclass} tchild = Class (tbase)

// Function addchild (const tagname: domstring): ixmlnode; overload; addchild (const tagname, namespaceuri: domstring): ixmlnode; overload; createelement (const tagordata, namespaceuri: domstring ): ixmlnode; createnode (const nameordata: domstring;

// Division and remainder: divmodconst A = 11; B = 3; var X, Y: word; begin showmessage (inttostr (a div B )); {divisible 3} showmessage (inttostr (a mod B); {remainder 2} divmod (a, B, x, y); showmessage (inttostr (x )); {3} showmessage (inttostr