RND
Syntax
rnd()
rnd
Description
Returns a number of type float in the range [0, 1) (i.e. 0 <= RND < 1), based on a random seed (see RANDOMIZE).
Examples
REM Function to a random number in the range [first, last), or {first <= x < last}.
Function rnd_range (first As Double, last As Double) As Float
Function = Rnd * (last - first) + first
End Function
REM seed the random number generator, so the sequence is not the same each time
Randomize
REM prints a random number in the range [0, 1], or {0 <= x < 1}.
Print Rnd
REM prints a random number in the range [0, 10], or {0 <= x < 10}.
Print Rnd * 10
REM prints a random integer number in the range [1, 11), or {1 <= x < 11}.
REM with integers, this is equivalent to [1, 10], or {1 <= n <= 10}.
Print Int(Rnd * 10) + 1
REM prints a random integer number in the range [69, 421], or {69 <= x < 421}.
REM this is equivalent to [69, 420], or {69 <= n <= 420}.
Print Int(rnd_range(69, 421))
Remarks
ZX BASIC RND is much faster than Sinclair BASIC RND, and produces different random sequences.
Its randomness is also much better (try plotting points at random x,y coords, and they look really random whilst in Sinclair BASIC diagonal lines begin to appear: this means there's a correlation between x, y points hence not very random).
Also, Sinclair BASIC RND has a periodicity of 2^16 (65536), whilst ZX BASIC RND has a periodicity of 2^32 (4,294,967,296).