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}}