V. Generating Random Numbers


Using The Random Function:
rand  = random();

The random() function generates a random number between 0 and 1 inclusively.

Example:

rand = random();             // generates a random number between [0-1] and places it in rand.


Generating A Random Integer Between A Range (Inclusively):

rand = rounddown((max_value - min_value + 1)*random(), 1) + min_value;

Example where the max value is 7, and  the min value is 2:

rand  = rounddown((7-2+1)*random(), 1) + 2;

Explanation:
rounddown((7-2+1)*random(), 1) first generates a random rational number between [0,1] inclusively which is
multiplied by 6 = (7-2+1), producing a rational number between [0-6] inclusively. The application of the
rounddown function then produces an integer between [0-5] with equal probability (see  III. Rounding Numbers).
Adding 2 scales the range by 2 resulting in production of an integer between [2-7] with equal probability.

 

Generating A Random Rational Number Between A Range (Inclusively):

value = (max_value – min_value)*random() + min_value;

Example:

rand = (10 – 5)*random() + 5;       //generates a random rational number between [5-10] which is stored rand.