Delphi Basics : High command

DelphiBasics

High
Function

Returns the highest value of a type or variable

System unit

function High(type or variable):Ordinal type;

Description

The High function returns the highest allowed value of either a type or variable of that type.

It only applies to characters, arrays, enumerations and short strings.

For arrays, it returns the higest index.

Notes

For multi-dimensional arrays, it returns the highest index of the first subarray (the left most definition of array range).

The size of an open array is given independent of the starting index of the array. It is the length of the array - 1.

Related commands

Low

Returns the lowest value of a type or variable

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Example code : High applied to character, array, enumeration and short strings

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))));
  ShowMessage('High(myChar)  = '+IntToStr(Ord(High(myChar))));
  ShowMessage('High(TArray)  = '+IntToStr(High(TArray)));
  ShowMessage('High(myArray) = '+IntToStr(High(myArray)));
  ShowMessage('High(TEnum)   = '+IntToStr(Ord(High(TEnum))));
  ShowMessage('High(myEnum)  = '+IntToStr(Ord(High(myEnum))));
  ShowMessage('High(TShort)  = '+IntToStr(Ord(High(TShort))));
  ShowMessage('High(myShort) = '+IntToStr(Ord(High(myShort))));
end;

Show full unit code

  High(TChar) = 255
  High(myChar) = 255
  High(TArray) = 7
  High(myArray) = 7
  High(TEnum) = 11
  High(myEnum) = 11
  High(TShort) = 255
  High(myShort) = 255