Mega Code Archive
Randomize - reposition the random number generator next value system unit
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procedure Randomize ;
Description
The Randomize procedure is used in conjunction with the Random function. It repositions the random number generator in its sequence of 232 pseudo random numbers.
Randomize uses the time of day as the seed for this repositioning, so should provide a reliable method of creating an unpredictable sequence of numbers, even if they are a part of a predetermined sequence.
Related commands
Random Generate a random floating point or integer number
RandomRange Generate a random integer number within a supplied range
RandSeed Reposition the Random number generator next value
Example code : Run this code twice to see the effect of Randomize
var
int : Integer;
i : Integer;
begin
// If you run this program twice, only the first 5 values
// will be guaranteed to be the same each time - randomize
// repositions into a different part of the pseudo sequence
// of random numbers.
// Get an integer random number in the range 1..100
ShowMessage('Fixed first 5 random numbers');
for i := 1 to 5 do
begin
int := 1 + Random(100); // The 100 value gives a range 0..99
ShowMessage('int = '+IntToStr(int));
end;
// Now randomize to reposition
Randomize;
ShowMessage('');
// Get an integer random number in the range 1..100
ShowMessage('Random next 5 numbers');
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;
Show full unit code
Fixed first 5 random numbers
int = 1
int = 4
int = 87
int = 21
int = 28
Random next 5 numbers
int = 35
int = 74
int = 45
int = 50
int = 31
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