The '''RND''' function returns a random number with a value between 0 (inclusive) and 1 (exclusive).


{{PageSyntax}} 
:: result! = [[RND]] [(''n'')]


{{Parameters}}
* ''n'' is a [[SINGLE]] numeric value that defines the behavior of the RND function but is '''NOT normally required''':
::n parameter omitted: Returns next random number in the sequence.
::n = 0: Return the last value returned.
::n < 0: Always returns the same value for any given n
::n > 0: the sequence of numbers generated will not change unless [[RANDOMIZE]] is initiated. 


{{PageDescription}}
* The random numbers generated range from 0 minimum to .9999999 maximum  [[SINGLE]] values that never equal 1.
* To get values in a range larger than 1, multiply RND with a number to get returns up to but not including that numerical value.
* To get values starting at a certain number, add that number to the RND result as RND minimums can be 0.
* If you need an integer range of numbers, like a dice roll, round it down to an [[INT]]. Add 1 to the maximum number with [[INT]].
* The random sequence is 2 ^ 24 or 16,777,216 entries long, which can allow repeated patterns in some procedures.
* Formulas for the [[INT|Integer]] or [[CINT|Closest Integer]] of ANY number range from ''min%''(lowest value) to ''max%''(greatest value): 
::* Using [[INT]]: randNum% = INT(RND * (max% - min% + 1)) + min%
::* Using [[CINT]]: randNum% = CINT(RND * (max% - min%)) + min%
* Use [[RANDOMIZE]] [[TIMER]] for different random number results each time a program is run. 
* [[RUN]] should reset the [[RANDOMIZE]] sequence to the starting [[RND]] function value.(Not yet in QB64)


''Example 1:'' Generating a random integer value between 1 and 6 (inclusive) using INT.
{{CodeStart}}
dice% = {{Cl|INT}}({{Cl|RND}} * 6) + 1 '' '' 'add one as INT value never reaches 6 
{{CodeEnd}}


''Example 2:'' Using uniform random numbers to create random numbers with a gaussian distribution ([http://en.wikipedia.org/wiki/Marsaglia_polar_method| Marsaglia's polar method]).
{{CodeStart}} '' ''
{{Cl|DO}}
  u! = {{Cl|RND}} * 2 - 1
  v! = {{Cl|RND}} * 2 - 1
  s! = u! * u! + v! * v!
{{Cl|LOOP}} {{Cl|WHILE}} s! >= 1 {{Cl|OR}} s! = 0
s! = SQR(-2 * {{Cl|LOG}}(s!) / s!) * 0.5
u! = u! * s!
v! = v! * s! '' ''
{{CodeEnd}}
:''Explanation:'' Values ''u!'' and ''v!'' are now two independent random numbers with gaussian distribution, centered at 0.


''Example 3:'' Random flashes from an explosion
{{CodeStart}} '' ''
{{Cl|SCREEN}} {{Cl|_NEWIMAGE}}(640, 480, 32)
{{Cl|RANDOMIZE}} {{Cl|TIMER}}
BC = 120 ' BALL COUNT
{{Cl|DIM}} ballx(1 {{Cl|TO}} BC)
{{Cl|DIM}} bally(1 {{Cl|TO}} BC)
{{Cl|DIM}} velx(1 {{Cl|TO}} BC)
{{Cl|DIM}} vely(1 {{Cl|TO}} BC)
{{Cl|DIM}} bsize(1 {{Cl|TO}} BC)
Y = {{Cl|INT}}({{Cl|RND}} * (400 - 100 + 1)) + 100
X0 = 325
Y0 = 300
Tmax = 150
DO
    {{Cl|FOR...NEXT|FOR}} p = 1 {{Cl|TO}} BC
        T = {{Cl|INT}}({{Cl|RND}} * (Tmax - 50 + 1)) + 50
        X = {{Cl|INT}}({{Cl|RND}} * (1000 + 500 + 1)) - 500
        velx(p) = (X - X0) / T '                       calculate velocity based on flight time
        vely(p) = -1 * (Y - .05 * (T ^ 2 + 20 * Y0)) / (T) ' verticle velocity
    {{Cl|NEXT}} p

    {{Cl|FOR...NEXT|FOR}} w = 1 {{Cl|TO}} BC
        bsize(w) = {{Cl|INT}}({{Cl|RND}} * (10 - 0 + 1)) + 0 'size
    {{Cl|NEXT}} w

    {{Cl|FOR...NEXT|FOR}} J = 1 {{Cl|TO}} Tmax
        {{Cl|_LIMIT}} 60
        {{Cl|CLS}}
        '{{Cl|FOR...NEXT|FOR}} i = 0 {{Cl|TO}} 255 {{Cl|STEP}} .5
        '{{Cl|CIRCLE}} (X0, Y0), i, {{Cl|_RGB}}(255 - i, 0, 0), 0, 3.147
        ' {{Cl|NEXT}} i

        R = {{Cl|INT}}({{Cl|RND}} * (25 - 20 + 1)) + 20 'random glimmer
        {{Cl|FOR...NEXT|FOR}} z = 1 {{Cl|TO}} BC
            ballx(z) = X0 + velx(z) * J
            bally(z) = Y0 - vely(z) * J + .5 * .1 * J ^ 2
        {{Cl|NEXT}} z

        {{Cl|FOR...NEXT|FOR}} d = 1 {{Cl|TO}} BC
            RCOL = {{Cl|INT}}({{Cl|RND}} * (255 - 0 + 1)) 'color
            {{Cl|FOR...NEXT|FOR}} i = 0 {{Cl|TO}} bsize(d) + 1 {{Cl|STEP}} .4 'draw balls
                {{Cl|CIRCLE}} (ballx(d), bally(d)), i, {{Cl|_RGBA}}(255, RCOL - (R * i), RCOL - R * i, 255)
            {{Cl|NEXT}} i
        {{Cl|NEXT}} d

        {{Cl|_DISPLAY}}

    {{Cl|NEXT}} J

{{Cl|LOOP}} {{Cl|UNTIL}} {{Cl|INKEY$}} <> "" '' ''
{{CodeEnd}} {{small|Code by Falcon}}


{{PageSeeAlso}}
* [[RANDOMIZE]], [[TIMER]]
* [[INT]], [[CINT]], [[FIX]]


{{PageNavigation}}
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