| rand | random real number procedure |
| Syntax | rand (var r : real)
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| Description | The rand statement is used to create a pseudo-random number in the range zero to one. For example, if x is a real number, after rand(x), x would have a value such as 0.729548 or 0.352879.
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| Example | This program repeatedly and randomly prints out Hi ho, hi ho or It's off to work we go.
var r : real
loop
rand ( r )
if r > 0.5 then
put "Hi ho, hi ho"
else
put "It's off to work we go"
end if
end loop
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| Details | The rand statement sets its parameter to the next value of a sequence of pseudo-random real numbers that approximates a uniform distribution over the range 0<r <1. Each time a program runs, rand uses a different pseudo-random number sequence. To get the same sequence (use Rand.Set). To use several sequences of repeatable pseudo-random number sequences, use the randseed and randnext procedures. In many languages, rand would be a function rather than a procedure. It has been designed as a procedure in Turing to respect the mathematical idea that every call to a function using the same arguments (or no arguments at all) should return the same value. If rand were a function, this would not be true.
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| See also | randint, randomize, randseed and randnext. See also predefined unit Rand.
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