Functionهای یونیت System (*دلفی*)

[ali643]

تابع قدر مطلق

 function Abs ( Number : Numeric type ) : Numeric type;

مثال

var

  float, bigFloat : single;

  int : Integer;

  varVar : Variant;



begin

  float    := -1.5;       // Small negative floating point number

  bigFloat := -4.56E100;  // Infinite negative floating point number

  int      := -7;         // Negative integer

  varVar   := '-98';      // Variants are converted to floating point!



  ShowMessage('Abs(float) = '+FloatToStr(Abs(float)));

  ShowMessage('Abs(bigFloat) = '+FloatToStr(Abs(bigFloat)));

  ShowMessage('Abs(int) = '+FloatToStr(Abs(int)));



  // Variants are converted into Extended floating types

  float := Abs(varVar);

  ShowMessage('Abs(varVar) = '+FloatToStr(float));

end;

تابع Addr

1  function Addr ( Variable name ) : Pointer; 

2  function Addr ( Function name ) : Pointer; 

3  function Addr ( Procedure name ) : Pointer; 

مثال

var

  myString  : string;

  ptrString : PString;

begin

  // Set up variable values

  myString := 'Hello there';



  ptrString := Addr(myString);

  ShowMessage('myString : '+ptrString^);

end;

تابع Arctan

 function ArcTan ( const Number : Extended ) : Extended;

مثال

var

  float : single;

begin

  // The ArcTan of PI/2 should give 1.0

  float := ArcTan(PI/2);

  ShowMessage('ArcTan of PI/2 = '+FloatToStr(float));

end;

تابع Assigned

1  function Assigned ( PointerName : Pointer ) : Boolean; 

2  function Assigned ( ObjectName   : TObject ) : Boolean; 

3  function Assigned ( MethodName   : Method ) : Boolean; 

مثال

var

  myPtr : PChar;



begin

  // Pointer variables are not set to nil by default

  if Assigned(myPtr)

  then ShowMessage('myPtr is not nil')

  else ShowMessage('myPtr is nil');



  // So we must set them to nil to be sure that they are undefined

  myPtr := Nil;

  if Assigned(myPtr)

  then ShowMessage('myPtr is still not nil')

  else ShowMessage('myPtr is nil');

end;

تابع BeginThread

function BeginThread ( SecurityAttr : Pointer; StackSize : LongWord; ThreadFunc : TThreadFunc; Param : Pointer; CreateFlags : LongWord; var ThreadId : LongWord ) : Integer;

مثال
تمام یونیت

unit Unit1;



interface



uses

  Forms, Dialogs, Windows, SysUtils;



type

  TMsgRecord = record

    thread : Integer;

    msg    : string[30];

  end;

  TForm1 = class(TForm)

    procedure FormCreate(Sender: TObject);

  end;



var

  Form1: TForm1;



Implementation

{$R *.dfm}        // Include form definitions



ThreadVar         // We must allow each thread its own instances

                  // of the passed record variable

  msgPtr : ^TMsgRecord;



// Private thread procedure to show a string

function ShowMsg(Parameter : Pointer) : Integer;

begin

  // Set up a 0 return value

  Result := 0;



  // Map the pointer to the passed data

  // Note that each thread has a separate copy of msgPtr

  msgPtr := Parameter;



  // Display this message

  ShowMessagePos('Thread '+IntToStr(msgPtr.thread)+' '+msgPtr.msg,

                 200*msgPtr.thread, 100);



  // End the thread

  EndThread(0);

end;



procedure TForm1.FormCreate(Sender: TObject);

var

  id1, id2 : LongWord;

  thread1, thread2 : Integer;

  msg1, msg2 : TMsgRecord;



begin

  // set up our display messages

  msg1.thread := 1;

  msg1.msg    := 'Hello World';

  msg2.thread := 2;

  msg2.msg    := 'Goodbye World';



  // Start the first thread running asking for users first name

  thread1 := BeginThread(nil,

                         0,

                         Addr(ShowMsg),

                         Addr(msg1),

                         0,

                         id1);



  // And also ask for the surname

  thread2 := BeginThread(nil,

                         0,

                         Addr(ShowMsg),

                         Addr(msg2),

                         0,

                         id2);



  // Ensure that the threads are only closed when all done

  ShowMessagePos('Press this when other dialogs finished.', 200, 300);



  // Finally, tidy up by closing the threads

  CloseHandle(thread1);

  CloseHandle(thread2);

end;



end.

تابع Chr

1  function Chr ( IntValue : Integer ) : AnsiChar; 

2  function Chr ( IntValue : Integer ) : WideChar; 

مثال

var

  tab  : char;

  crlf : string;

begin

  // Show the use of Chr

  tab := Chr(9);

  crlf := Chr(13)+Chr(10);

  ShowMessage('Hello'+tab+'World');

  ShowMessage('');

  ShowMessage('Hello'+crlf+'World');

  ShowMessage('');



  // Show the equivalent use of ^

  tab := ^I;  // I = 9th capital of the alphabet

  crlf := ^M^J;  // M = 13th, J = 10th letters

  ShowMessage('Hello'+tab+'World');

  ShowMessage('');

  ShowMessage('Hello'+crlf+'World');

end;

تابع Copy

1  function Copy ( Source : string; StartChar, Count : Integer ) : string; 

2  function Copy ( Source : array; StartIndex, Count : Integer ) : array; 

مثال String copy

var

  Source, Target : string;



begin

  Source := '12345678';

  Target := Copy(Source, 3, 4);

  ShowMessage('Target : '+Target);

end;

مثال Array copy

var 

  i : Integer;

  Source, Target : array of Integer;



begin

  SetLength(Source, 8);



  for i := 1 to 8 do   // Build the dynamic source array

    Source[i-1] := i;   // Remember that arrays start at index 0



  Target := Copy(Source, 3, 4);



  for i := 0 to Length(Target) -1 do   // Display the created array

    ShowMessage('Target['+IntToStr(i)+  '] : '+IntToStr(Target[i]));

end;

تابع Cos

 function Cos ( const Number : Extended ) : Extended;

مثال

var

  float : single;

begin

  // The Sine of 60 degrees = 0.5

  float := Cos(PI/3);   // = 180/3 = 60 degrees

  ShowMessage('Cos(PI/3) = '+FloatToStr(float));

end;

تابع Eof

 function Eof ( var FileHandle : TextFile ) ;

مثال

var

  myFile : TextFile;

  text   : string;



begin

  // Try to open the Test.txt file for writing to

  AssignFile(myFile, 'Test.txt');

  ReWrite(myFile);



  // Write a couple of well known words to this file

  WriteLn(myFile, 'Hello');

  WriteLn(myFile, 'World');



  // Close the file

  CloseFile(myFile);



  // Reopen the file in read only mode

  Reset(myFile);



  // Display the file contents

  while not Eof(myFile) do

  begin

    ReadLn(myFile, text);

    ShowMessage(text);

  end;



  // Close the file for the last time

  CloseFile(myFile);

end;

تابع Eoln

 function Eoln ( var FileHandle : TextFile ) : Boolean;

مثال

var

  myFile : TextFile;

  letter : char;

  text   : string;



begin

  // Try to open the Test.txt file for writing to

  AssignFile(myFile, 'Test.txt');

  ReWrite(myFile);



  // Write lines of text to the file

  WriteLn(myFile, 'Hello');

  WriteLn(myFile, 'To you');



  // Close the file

  CloseFile(myFile);



  // Reopen the file for reading

  Reset(myFile);



  // Display the file contents

  while not Eof(myFile) do

  begin

    // Proces one line at a time

    ShowMessage('Start of a new line :');

    while not Eoln(myFile) do

    begin

      Read(myFile, letter);   // Read and display one letter at a time

      ShowMessage(letter);

    end;

    ReadLn(myFile, text);

  end;



  // Close the file for the last time

  CloseFile(myFile);

end;

تابع Exp

 function Exp ( Number : Extended ) : Extended;

مثال

var

  float : Double;

begin

  // Get the natural logarithm of 2

  float := Ln(2);



  // Show this value

  ShowMessage('Ln(2) = '+FloatToStr(float));



  // Get the exponent of this value - reverses the Ln operation

  float := Exp(float);



  // Show this value

  ShowMessage('Exp(Ln(2)) = '+FloatToStr(float));

end;

تابع FilePos

1  function FilePos ( var FileHandle : File; ) : LongInt; 

2  function FilePos ( car FileHandle : TextFile; ) ; 

مثال

var

  myWord, myWord1, myWord2, myWord3 : Word;

  myFile : File of Word;



begin

  // Try to open the Test.cus binary file in write only mode

  AssignFile(myFile, 'Test.cus');

  ReWrite(myFile);



  // Write a few lines of Word data to the file

  myWord1 := 123;

  myWord2 := 456;

  myWord3 := 789;

  Write(myFile, myWord1, myWord2, myWord3);



  // Close the file

  CloseFile(myFile);



  // Reopen the file in read only mode

  FileMode := fmOpenRead;

  Reset(myFile);



  // Display the file contents

  while not Eof(myFile) do

  begin

    Read(myFile, myWord);

    // Note - FilePos shows the after read position

    ShowMessage('Record '+

                IntToStr(FilePos(myFile))+' = '+

                IntToStr(myWord));

  end;



  // Close the file for the last time

  CloseFile(myFile);

end;

تابع FileSize

 function FileSize ( var FileHandle : File; ) : Integer;

مثال

var

  myWord, myWord1, myWord2, myWord3 : Word;

  myFile : File of Word;



begin

  // Try to open the Test.cus binary file in write only mode

  AssignFile(myFile, 'Test.cus');

  ReWrite(myFile);



  // Before writing to the file, show the file size

  ShowMessage('File size = '+IntToStr(FileSize(myFile)));



  // Write a few lines of Word data to the file

  myWord1 := 123;

  myWord2 := 456;

  myWord3 := 789;

  Write(myFile, myWord1, myWord2, myWord3);



  // Before closing the file, show the new file size

  ShowMessage('File size now = '+IntToStr(FileSize(myFile)));



  // Close the file

  CloseFile(myFile);

end;

تابع Frac

 function Frac ( const Number : Extended ) : Extended;

مثال

begin

  ShowMessage('Round(12.75) = '+IntToStr(Round(12.75)));

  ShowMessage('Trunc(12.75) = '+IntToStr(Trunc(12.75)));

  ShowMessage('  Int(12.75) = '+FloatToStr(Int(12.75)));

  ShowMessage(' Frac(12.75) = '+FloatToStr(Frac(12.75)));

end;

تابع GetLastError

 function GetLastError : Integer;

مثال

begin

  if DeleteFile('CanDeletMe.txt')

  then ShowMessage('File deleted OK')

  else ShowMessage('File not deleted, error code = '+

                   IntToStr(GetLastError));

end;

تابع GetMem

function GetMem ( var StoragePointer : Pointer; StorageSize : Integer ) ;

مثال

type

  TRecord = Record

    name : string[10];

    age  : Byte;

  end;



var

  recPointer : ^TRecord;



begin

  // Allocate storage for three records

  // Note : It is better to use New for this

  // It is used here for illustration purposes only

  GetMem(recPointer, 3 * SizeOf(TRecord));



  // Fill out these 3 records with values

  recPointer.name := 'Brian';

  recPointer.age  := 23;



  Inc(recPointer);

  recPointer.name := 'Jim';

  recPointer.age  := 55;



  Inc(recPointer);

  recPointer.name := 'Sally';

  recPointer.age  := 38;



  // Now display these values

  Dec(recPointer, 2);

  ShowMessageFmt('%s is %d',[recPointer.name, recPointer.age]);

  Inc(recPointer);

  ShowMessageFmt('%s is %d',[recPointer.name, recPointer.age]);

  Inc(recPointer);

  ShowMessageFmt('%s is %d',[recPointer.name, recPointer.age]);

end;

تابع Hi

 function Hi ( IntValue : Integer ) : Byte;

مثال

var

  i : Integer;



begin

  i := $2345;  // $2345 hex : $23 hi byte, $45 lo byte

  ShowMessage(Format('Integer = $%x', [i]));

  ShowMessage(Format('Hi byte = $%x', [Hi(i)]));

  ShowMessage(Format('Lo byte = $%x', [Lo(i)]));

end;

تابع High

 function High ( type or variable ) : Ordinal type;

مثال

type

  // Declare character, array and enumerated data types

  TChar  = char;

  TArray = array [3..7] of Integer;

  TEnum  = (Mon=5, Tue, Wed, Thu, Fri, Sat, Sun);

  TShort = shortstring;



var

  // Declare variables of the above data types

  myChar  : TChar;

  myArray : TArray;

  myEnum  : TEnum;

  myShort : TShort;



begin

  // Show the high values of the types and variables

  ShowMessage('High(TChar)   = '+IntToStr(Ord(High(TChar))&#4  1;);

  ShowMessage('High(myChar)  = '+IntToStr(Ord(High(myChar))&#  41;);

  ShowMessage('High(TArray)  = '+IntToStr(High(TArray)));

  ShowMessage('High(myArray) = '+IntToStr(High(myArray)));

  ShowMessage('High(TEnum)   = '+IntToStr(Ord(High(TEnum))&#4  1;);

  ShowMessage('High(myEnum)  = '+IntToStr(Ord(High(myEnum))&#  41;);

  ShowMessage('High(TShort)  = '+IntToStr(Ord(High(TShort))&#  41;);

  ShowMessage('High(myShort) = '+IntToStr(Ord(High(myShort))&  #41;);

end;

تابع Int

function Int ( const Number : Extended ) : Extended;

مثال

begin

  ShowMessage('Round(12.75) = '+IntToStr(Round(12.75)));

  ShowMessage('Trunc(12.75) = '+IntToStr(Trunc(12.75)));

  ShowMessage('  Int(12.75) = '+FloatToStr(Int(12.75)));

  ShowMessage(' Frac(12.75) = '+FloatToStr(Frac(12.75)));

end;

تابع IOResult

function IOResult : Integer;

مثال

var

  error : Integer;



begin

  // Try to create a new subdirectory in the current directory

  // Switch off I/O error checking

  {$IOChecks off}

  MkDir('TempDirectory');



  // Did the directory get created OK?

  error := IOResult;

  if error = 0

  then ShowMessage('Directory created OK')

  else ShowMessageFmt('Directory creation failed with error %d',[error]);



  // Try to create the directory again - this will fail!

  MkDir('TempDirectory');

  error := IOResult;  // Save the return code

  if error = 0

  then ShowMessage('Directory created OK again')

  else ShowMessageFmt('Repeat creation failed with error %d',[error]);



  // Delete the directory to tidy up

  RmDir('TempDirectory');



  // Switch IO checking back on

  {$IOChecks on}

end;

تابع IsMultiThread

function IsMultiThread : Boolean;

مثال یونیت کامل

unit Unit1;



interface



uses

  Forms, Dialogs, Windows, SysUtils;



type

  TMsgRecord = record

    msg    : string[30];

  end;

  TForm1 = class(TForm)

    procedure FormCreate(Sender: TObject);

  end;



var

  Form1: TForm1;



Implementation

{$R *.dfm}        // Include form definitions



ThreadVar         // We must allow each thread its own instances

                  // of the passed record variable

  msgPtr : ^TMsgRecord;



// Private thread procedure to show a string

function ShowMsg(Parameter : Pointer) : Integer;

begin

  // Set up a 0 return value

  Result := 0;



  // Map the pointer to the passed data

  // Note that each thread has a separate copy of msgPtr

  msgPtr := Parameter;



  // Display this message

  ShowMessagePos('Thread message : '+msgPtr.msg, 200, 100);



  // End the thread

  EndThread(0);

end;



procedure TForm1.FormCreate(Sender: TObject);

var

  id1         : LongWord;

  thread1     : Integer;

  msg1        : TMsgRecord;

  showMsgFunc : TThreadFunc;



begin

  // Set up the thread function

  showMsgFunc := Addr(ShowMsg);



  // Set up our display messages

  msg1.msg    := 'Hello World';



  // Inidicate that we are not running a thread

  if IsMultiThread

  then ShowMessage('Multi-threaded')

  else ShowMessage('Single threaded');



  // Start the first thread running asking for users first name

  thread1 := BeginThread(nil,

                         0,

                         showMsgFunc,

                         Addr(msg1),

                         0,

                         id1);



  // Inidicate that we are running a thread

  if IsMultiThread

  then ShowMessage('Multi-threaded')

  else ShowMessage('Single threaded');



  // Ensure that the thread is only closed when all done

  ShowMessagePos('Press this when thread dialog finished.', 200, 300);



  // Finally, tidy up by closing the threads

  CloseHandle(thread1);

end;



end.

تابع Length

1  function Length ( const SourceString : string ) : Integer; 

2  function Length ( const  SourceArray : array ) : Integer; 

مثال

var

  openArray  : array of char;

  fixedArray : array[2..4] of Integer;

  multiArray : array[2..4, 1..9] of Integer;

  shortStr   : shortstring;

  longStr    : string;

  i          : Integer;



begin

  // Define the length of the open array

  SetLength(openArray, 17);



  // Show the length of the arrays

  ShowMessage('Length of openArray = '+IntToStr(Length(openArray)))  ;

  ShowMessage('Length of fixedArray = '+IntToStr(Length(fixedArray))&#41  ;;

  ShowMessage('Length of multiArray = '+IntToStr(Length(multiArray))&#41  ;;



  // Assign to the strings

  shortStr := 'ABCDEFGH';

  longStr  := '12345678901234567890';

  ShowMessage('Length of shortStr = '+IntToStr(Length(shortStr)));

  ShowMessage('Length of longStr = '+IntToStr(Length(longStr)));



  // Display one letter at a time from the short string

  for i := 1 to Length(shortStr) do

    ShowMessage('Letter '+IntToStr(i)+' = '+shortStr[i]);

end;

تابع Ln

function Ln ( Number : Extended ) : Extended;

مثال

var

  float : Double;

begin

  // Get the natural logarithm of 2

  float := Ln(2);



  // Show this value

  ShowMessage('Ln(2) = '+FloatToStr(float));



  // Get the exponent of this value - reverses the Ln operation

  float := Exp(float);



  // Show this value

  ShowMessage('Exp(Ln(2)) = '+FloatToStr(float));

end;

تابع Lo

[code] function Lo ( IntValue : Integer ) : Byte;[/code]

مثال

var

  i : Integer;



begin

  i := $2345;  // $2345 hex : $23 hi byte, $45 lo byte

  ShowMessage(Format('Integer = $%x', [i]));

  ShowMessage(Format('Hi byte = $%x', [Hi(i)]));

  ShowMessage(Format('Lo byte = $%x', [Lo(i)]));

end;

تابع

function Low ( type or variable ) : Ordinal type; 

مثال

type

  // Declare character, array and enumerated data types

  TChar  = char;

  TArray = array [3..7] of Integer;

  TEnum  = (Mon=5, Tue, Wed, Thu, Fri, Sat, Sun);

  TShort = shortstring;



var

  // Declare variables of the above data types

  myChar  : TChar;

  myArray : TArray;

  myEnum  : TEnum;

  myShort : TShort;



begin

  // Show the low values of the types and variables

  ShowMessage('Low(TChar)    = '+IntToStr(Ord(Low(TChar))&#41  ;);

  ShowMessage('Low(myChar)   = '+IntToStr(Ord(Low(myChar))&#4  1;);



  ShowMessage('Low(TArray)   = '+IntToStr(Low(TArray)));

  ShowMessage('Low(myArray)  = '+IntToStr(Low(myArray)));

  ShowMessage('High(myArray) = '+IntToStr(High(myArray)));



  ShowMessage('Low(TEnum)    = '+IntToStr(Ord(Low(TEnum))&#41  ;);

  ShowMessage('Low(myEnum)   = '+IntToStr(Ord(Low(myEnum))&#4  1;);

  ShowMessage('High(myEnum)  = '+IntToStr(Ord(High(myEnum))&#  41;);



  ShowMessage('Low(TShort)   = '+IntToStr(Ord(Low(TShort))&#4  1;);

  ShowMessage('Low(myShort)  = '+IntToStr(Ord(Low(myShort))&#  41;);

end;

تابع Odd

function Odd ( Number : Integer | Int64 ) : Boolean; 

مثال

var

  i : Integer;



begin

  // Display all odd numbers in the range 1 to 9

  for i := 1 to 9 do

    if Odd(i) then ShowMessageFmt('%d is odd',[i]);

end;

تابع Ord

1  function Ord ( Arg : AnsiChar | Char | WideChar | Enumeration | Integer ) : Integer; 

2  function Ord ( Arg : Int64 ) : Int64 

مثال

var

  A   : AnsiChar;

  C   : Char;

  W   : WideChar;

  E   : Boolean;

  I   : Integer;

  I64 : Int64;



begin

  // Set the ordinal type values

  A   := 'A';

  C   := 'C';

  W   := 'W';

  E   := True;

  I   := 22;

  I64 := 64;



  // And show the value of each

  ShowMessage('A = '+IntToStr(Ord(A)));

  ShowMessage('C = '+IntToStr(Ord(C)));

  ShowMessage('W = '+IntToStr(Ord(W)));

  ShowMessage('E = '+IntToStr(Ord(E)));

  ShowMessage('I = '+IntToStr(Ord(I)));

  ShowMessage('I64 = '+IntToStr(Ord(I64)));

end;

تابع ParamCount

 function ParamCount : Integer;

مثال

var

  cmd : string;

  i : Integer;



begin

  // Before running this code, use the Run/parameters menu option

  // to set the following command line parameters : -parm1 -parm2

  cmd := CmdLine;

  ShowMessage(cmd);     // Show the execution command + parameters



  // How many parameters were passed?

  ShowMessage('There are '+IntToStr(ParamCount)+' parameters');



  // Show these parameters - note that the 0th parameter is the

  // execution command on Windows

  for i := 0 to ParamCount do

    ShowMessage('Parameter '+IntToStr(i)+' = '+ParamStr(i));

end;

تابع ParamStr

function ParamStr ( ParmIndex : Integer ) : string;

مثال

var

  cmd : string;

  i : Integer;



begin

  // Before running this code, use the Run/parameters menu option

  // to set the following command line parameters : -parm1 -parm2



  // Show these parameters - note that the 0th parameter is the

  // execution command on Windows

  for i := 0 to ParamCount do

    ShowMessage('Parameter '+IntToStr(i)+' = '+ParamStr(i));

end;

تابع Pi

 function Pi : Extended;

مثال

var

  myPi : Extended;

  diam : Integer;

begin

  diam := 10;



  // Show circumference and the area of a circle

  // with diameter - 10 cm

  ShowMessage('     Diameter = '+IntToStr(diam));

  ShowMessage('Circumference = '+FloatToStr(Pi*diam));

  ShowMessage('         Area = '+FloatToStr(Pi*(diam/2)*(diam/2)));

end;

تابع Pos

 function Pos ( const Needle, HayStack : string ) : Integer;

تابع Pred

function Pred ( const Ordinal Value ) : Ordinal type;

مثال

type

  TSuit = (Hearts, Clubs, Diamonds, Spades);



var

  Character : char;

  Number    : Integer;

  Card      : TSuit;



begin

  // We can decrement characters

  Character := 'B';



  ShowMessage('Character : '+Character);

  Character := Pred(Character);

  ShowMessage('Character-1 : '+Character);



  // We can decrement numbers

  Number := 23;



  ShowMessage('Number : '+IntToStr(Number));

  Number := Pred(Number);

  ShowMessage('Number-1 : '+IntToStr(Number));



  // We can decrement enumerations

  Card := Clubs;



  ShowMessage('Card starts at Clubs');

  Card := Pred(Card);

  if Card = Hearts then ShowMessage('Card is now Hearts');

  if Card = Clubs then ShowMessage('Card is now Clubs');

  if Card = Diamonds then ShowMessage('Card is now Diamonds');

  if Card = Spades then ShowMessage('Card is now Spades');

end;

تابع Random

1  function Random : Extended; 

2  function Random ( LimitPlusOne : Integer ) : Integer; 

مثال

var

  float : single;

  int   : Integer;

  i     : Integer;



begin

  // Get floating point random numbers in the range 0 <= Number < 1.0

  for i := 1 to 5 do

  begin

    float := Random;

    ShowMessage('float = '+FloatToStr(float));

  end;



  ShowMessage('');



  // Get an integer random number in the range 1..100

  for i := 1 to 5 do

  begin

    int := 1 + Random(100);    // The 100 value gives a range 0..99

    ShowMessage('int = '+IntToStr(int));

  end;

end;

تابع Round

 function Round ( const Number : Extended ) : Int64;

مثال

begin

  ShowMessage('Round(12.75) = '+IntToStr(Round(12.75)));

  ShowMessage('Trunc(12.75) = '+IntToStr(Trunc(12.75)));

  ShowMessage('  Int(12.75) = '+FloatToStr(Int(12.75)));

  ShowMessage(' Frac(12.75) = '+FloatToStr(Frac(12.75)));

end;

تابع SeekEof

function SeekEof ( {var FileHandle : File} ) : Boolean;

مثال

var

  myFile : TextFile;

  number : Integer;



begin

  // Try to open the Test.txt file for writing to

  AssignFile(myFile, 'Test.txt');

  ReWrite(myFile);



  // Write numbers in a string

  WriteLn(myFile, '1 2 3 4   ');   // White space at the end



  // Write numbers as separate parameters

  WriteLn(myFile, 5, ' ', 6, ' ', 7, ' ');  // Results in '5 6 7 ' text



  // Close the file

  CloseFile(myFile);



  // Reopen the file for reading

  Reset(myFile);



  // Display the file contents

  while not SeekEof(myFile) do

  begin

    // Read numbers one at a time

    ShowMessage('Start of a new line');

    while not SeekEoln(myFile) do

    begin

      Read(myFile, number);

      ShowMessage(IntToStr(number));

    end;



    // Now move to the next line

    ReadLn(myFile);

  end;



  // Close the file for the last time

  CloseFile(myFile);

end;

تابع SeekEoln

function SeekEoln ( {var FileHandle : File} ) : Boolean;

مثال

var

  myFile : TextFile;

  number : Integer;



begin

  // Try to open the Test.txt file for writing to

  AssignFile(myFile, 'Test.txt');

  ReWrite(myFile);



  // Write numbers in a string

  WriteLn(myFile, '1 2 3 4   ');   // White space at the end



  // Write numbers as separate parameters

  WriteLn(myFile, 5, ' ', 6, ' ', 7, ' ');  // Results in '5 6 7 ' text



  // Close the file

  CloseFile(myFile);



  // Reopen the file for reading

  Reset(myFile);



  // Display the file contents

  while not SeekEof(myFile) do

  begin

    // Read numbers one at a time

    ShowMessage('Start of a new line');

    while not SeekEoln(myFile) do

    begin

      Read(myFile, number);

      ShowMessage(IntToStr(number));

    end;



    // Now move to the next line

    ReadLn(myFile);

  end;



  // Close the file for the last time

  CloseFile(myFile);

end;

تابع Sin

function Sin ( const Number : Extended ) : Extended;

مثال

var

  float : single;

begin

  // The Sine of 30 degrees = 0.5

  float := Sin(PI/6);   // = 180/6 = 30 degrees

  ShowMessage('Sin(PI/6) = '+FloatToStr(float));

end;

تابع SizeOf

1  function SizeOf ( Variable : Any type ) : Integer; 

2  function SizeOf ( Type ) : Integer; 

مثال

var

  intNumber : Integer;

  extNumber : Extended;

  sentence  : string;



begin

  // Display the sizes of a number of data types

  ShowMessageFmt('  SizeOf(Integer) = %d',[SizeOf(Integer)]);

  ShowMessageFmt('SizeOf(intNumber) = %d',[SizeOf(intNumber)]);

  ShowMessageFmt(' SizeOf(Extended) = %d',[SizeOf(Extended)]);

  ShowMessageFmt('SizeOf(extNumber) = %d',[SizeOf(extNumber)]);



  // String types and variables are pointers to the actual strings

  sentence := 'A long sentence, certainly longer than 4';

  ShowMessageFmt('   SizeOf(string) = %d',[SizeOf(string)]);

  ShowMessageFmt(' SizeOf(sentence) = %d',[SizeOf(sentence)]);

end;

تابع Slice

function Slice ( SourceArray : array; Count : Integer ) : array;

مثال

var

  i : Integer;

  Source : array[0..4] of Integer;



begin

  // Create the source array with 0..4 values for elements 0..4

  for i := 0 to 4 do

    Source[i] := i;



  // Use the Slice command to pass just the first 3 elements of Source as

  // an open array to the ShowSlice procedure below.

  ShowSlice(Slice(Source, 3));

end;



// Show an array of unknown size - it is passed as an 'Open' array

procedure TForm1.ShowSlice(SubArray : array of Integer);

var

  i : Integer;



begin

  // Show every element of this array

  for i := 0 to Length(SubArray)-1 do

    ShowMessage('SubArray['+IntToStr(i&#41  ;+'] : '+ IntToStr(SubArray[i]));

end;

تابع Sqr

1  function Sqr ( Number :  Integer ) : Integer; 

2  function Sqr ( Number :    Int64 ) : Int64; 

3  function Sqr ( Number : Extended ) : Extended; 

مثال

var

  number, squared : Byte;

  float : Extended;



begin

  // The square of 15 = 225

  number  := 15;

  squared := Sqr(number);

  ShowMessageFmt('%d squared = %d',[number, squared]);



  // The square of 17 = 289

  // But result exceeds byte size, so result = 289 MOD 256 = 33

  number  := 17;

  squared := Sqr(number);

  ShowMessageFmt('%d squared = %d (see code above)',[number, squared]);



  // The square of infinity is still infinity

  float := Infinity;

  float := Sqr(float);

  ShowMessageFmt('Infinity squared = %f',[float]);

end;

تابع Sqrt

function Sqrt ( Number :  Extended ) : Extended;

مثال

var

  number, squareRoot : Extended;



begin

  // The square root of 225 = 15

  number  := 225;

  squareRoot := Sqrt(number);

  ShowMessageFmt('Square root of %f = %f',[number, squareRoot]);



  // The square root of 3.456 = 1.859...

  number  := 3.456;

  squareRoot := Sqrt(number);

  ShowMessageFmt('Square root of %7.3f = %12.12f',[number, squareRoot]);



  // The square root of infinity is still infinity

  number := Infinity;

  number := Sqrt(number);

  ShowMessageFmt('Square root of Infinity = %f',[number]);

end;

تابع StringOfChar ( Re

function StringOfChar ( RepeatCharacter : Char; RepeatCount : Integer ) : string;

مثال

var

  text, line : string;



begin

  // Write a heading with -'s as underline characters

  text := '1.An introduction to life as we know it';

  line := StringOfChar('-', Length(text));



  // Display our underlined heading

  ShowMessage(text);

  ShowMessage(line);

end;

تابع StringToWideChar

function StringToWideChar ( const SourceString : string; TargetBuffer : PWideChar; TargetSize : Integer ) : PWideChar;

مثال

var

  wideChars   : array[0..11] of WideChar;

  myString    : String;



begin

  // Set up our string

  myString := 'Hello World';



  // Copy to a WideChar format in our array

  StringToWideChar(myString, wideChars, 12);



  // Show what the copy gave

  ShowMessage(WideCharToString(wideChars&#41  ;);

end;

تابع Succ

 function Succ ( const Ordinal Value ) : Ordinal type;

مثال

type

  TSuit = (Hearts, Clubs, Diamonds, Spades);



var

  Character : char;

  Number    : Integer;

  Card      : TSuit;



begin

  // We can increment characters

  Character := 'A';



  ShowMessage('Character : '+Character);

  Character := Succ(Character);

  ShowMessage('Character+1 : '+Character);



  // We can increment numbers

  Number := 23;



  ShowMessage('Number : '+IntToStr(Number));

  Number := Succ(Number);

  ShowMessage('Number+1 : '+IntToStr(Number));



  // We can increment enumerations

  Card := Clubs;



  ShowMessage('Card starts at Clubs');

  Card := Succ(Card);

  if Card = Hearts then ShowMessage('Card is now Hearts');

  if Card = Clubs then ShowMessage('Card is now Clubs');

  if Card = Diamonds then ShowMessage('Card is now Diamonds');

  if Card = Spades then ShowMessage('Card is now Spades');

end;

تابع Trunc

 function Trunc ( const Number : Extended ) : Integer;

مثال

begin

  ShowMessage('Round(12.75) = '+IntToStr(Round(12.75)));

  ShowMessage('Trunc(12.75) = '+IntToStr(Trunc(12.75)));

  ShowMessage('  Int(12.75) = '+FloatToStr(Int(12.75)));

  ShowMessage(' Frac(12.75) = '+FloatToStr(Frac(12.75)));

end;

تابع UpCase

 function UpCase ( Letter : Char ) : Char;

مثال

var

  lower, upper : char;



begin

  // Convert a lower case letter to upper case

  lower := 'g';

  upper := UpCase(lower);



  // Display these letters

  ShowMessage('lower = '+lower+' upper = '+upper);

end;

تابع WideCharToString

 function WideCharToString ( Source : PWideChar; ) : string;

مثال

var

  wideCharArray : array[0..5] of WideChar;

  myString      : String;



begin

  // Set up our WideChar array

  wideCharArray[0] := 'H';

  wideCharArray[1] := 'e';

  wideCharArray[2] := 'l';

  wideCharArray[3] := 'l';

  wideCharArray[4] := 'o';

  wideCharArray[5] := #0;   // Terminates WideChar strings



  // Copy to a normal string

  myString := WideCharToString(wideCharArray);



  // Show what the copy gave

  ShowMessage(myString);

end;

توضیحات فارسی هر Function رو اگه اساتید کمک کنند همین جا پست می کنم

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FloatToStr