Cross Ref > Data Structures

Delphi supports both static and dynamic arrays as well as single and multi dimensional arrays.

var
  MyArray: array[0..3] of string;
  i: Integer;
begin
  MyArray[0] := 'Mike';
  MyArray[1] := 'Lisa';
  MyArray[2] := 'Felicia';
  MyArray[3] := 'Nathan';

  for i := 0 to High(MyArray) do
    ShowMessage(MyArray[i]);
end;

 Delphi Array (x=Array[0..3] of string;)  

An associative array links a set of keys to a set of values. In Java, associative arrays are implemented as Maps.

This will print "Arizona."

import java.util.*;

public class Maps 
{
    public static void main(String[] args) 
    {
        Map states = new HashMap();
        
        states.put("CA", "California");
        states.put("FL", "Florida");
        states.put("AZ", "Arizona");

        System.out.println(states.get("AZ"));
    }
}

 Associative Arrays in Java (a Map)

Object Pascal doesn't have a native associative array, but you can use a TStringList the same way. (Alternatively, search the Internet for TStringHash and THashedStringList classes for implementations of a true associative array).

var
  StateList : TStringList;
begin
  StateList := TStringList.Create; 

  StateList.CommaText := 'CA=California, FL=Florida';

  ShowMessage('FL is ' + StateList.Values['FL']);
end;

 Associative Arrays in Delphi/Object Pascal (Use TStringList)

Java does not offer developer defined pointers.

Although pointer data types in Delphi coding are less important and not required for most general coding, Delphi fully supports developer defined pointers. Use a carrot (^) to declare a pointer data type. Use the @ operator or Addr function to return the current address of a variable.

Delphi provides typed pointer types such as PChar and PExtended as well as a generic point to anything Pointer type.

Nil is a special pointer value that you can assign to any type of pointer. Nil never points to any valid memory and indicates an unassigned or empty pointer.

//Declare a pointer of type integer.

PCounter : ^Integer;

//Assign a value to the location of a pointer.

//Also known as dereferencing.

PCounter^ := 8;

//Assign address of A to B.

PointerB := @PointerA;  //or...PointerB := Addr(PointerA);