[Overview][Constants][Types][Classes][Procedures and functions][Variables][Index] Reference for unit 'System' (#rtl)

Random

Generate random number

Declaration

Source position: line 0

function Random(

  l: LongInt

):LongInt;

function Random(

  l: Int64

):Int64;

function Random: extended;

Description

Random returns a random number larger or equal to 0 and strictly less than L. If the argument L is omitted, a Real number between 0 and 1 is returned. (0 included, 1 excluded)

Errors

None.

See also

Randomize

  

Initialize random number generator

Example

Program Example49;

{ Program to demonstrate the Random and Randomize functions. }

Var I,Count,guess : Longint;
    R : Real;

begin
  Randomize; { This way we generate a new sequence every time
               the program is run}
  Count:=0;
  For i:=1 to 1000 do
    If Random>0.5 then inc(Count);
  Writeln ('Generated ',Count,' numbers > 0.5');
  Writeln ('out of 1000 generated numbers.');
  count:=0;
  For i:=1 to 5 do
    begin
    write ('Guess a number between 1 and 5 : ');
    readln(Guess);
    If Guess=Random(5)+1 then inc(count);
    end;
  Writeln ('You guessed ',Count,' out of 5 correct.');
end.
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