BrainF__k interpreter test case

language

>   Increment data pointer so that it points to next location in memory.

<   Decrement data pointer so that it points to previous locaion in memory.

+   Increment the byte pointed by data pointer by 1. If it is already at its maximum value, 255, then new value will be 0.

-   Decrement the byte pointed by data pointer by 1. If it is at its minimum value, 0, then new value will be 255.

.   Output the character represented by the byte at the data pointer.

,   Read one byte and store it at the memory location pointed by data pointer.

[   If the byte pointed by data pointer is zero, then move instruction pointer to next matching ']', otherwise move instruction pointer to next command.

]   If the byte pointed by data pointer is non-zero, then move instruction pointer to previous matching '[' command, otherwise to next command.

Every character is ignored (comments)

output

    0! = 1
    1! = 1
    2! = 2
    3! = 6
    4! = 24
    5! = 120

program

  +++++++++++++++++++++++++++++++++           c1v33 : ASCII code of !
  >++++++++++++++++++++++++++++++
  +++++++++++++++++++++++++++++++             c2v61 : ASCII code of =
  >++++++++++                     c3v10 : ASCII code of EOL
  >++++++                        c4v7  : quantity of numbers to be calculated
  >                           c5v0  : current number (one digit)
  >+                          c6v1  : current value of factorial (up to three digits)
  <<                          c4    : loop counter
  [                           block : loop to print one line and calculate next
  >++++++++++++++++++++++++++++++++++++++++++++++++.  c5    : print current number
  ------------------------------------------------    c5    : back from ASCII to number
  <<<<.-.>.<.+                        c1    : print !_=_

  >>>>>                           block : print c6 (preserve it)
  >                           c7v0  : service zero
  >++++++++++                     c8v10 : divizor
  <<                          c6    : back to dividend
  [->+>-[>+>>]>[+[-<+>]>+>>]<<<<<<]           c6v0  : divmod algo borrowed from esolangs; results in 0 n d_n%d n%d n/d
  >[<+>-]                         c6    : move dividend back to c6 and clear c7
  >[-]                            c8v0  : clear c8

  >>                          block : c10 can have two digits; divide it by ten again
  >++++++++++                     c11v10: divizor
  <                           c10   : back to dividend
  [->-[>+>>]>[+[-<+>]>+>>]<<<<<]              c10v0 : another divmod algo borrowed from esolangs; results in 0 d_n%d n%d n/d
  >[-]                            c11v0 : clear c11
  >>[++++++++++++++++++++++++++++++++++++++++++++++++.[-]]c13v0 : print nonzero n/d (first digit) and clear c13
  <[++++++++++++++++++++++++++++++++++++++++++++++++.[-]] c12v0 : print nonzero n%d (second digit) and clear c12
  <<<++++++++++++++++++++++++++++++++++++++++++++++++.[-] c9v0  : print any n%d (last digit) and clear c9

  <<<<<<.                         c3    : EOL
  >>+                         c5    : increment current number
                              block : multiply c6 by c5 (don't preserve c6)
  >[>>+<<-]                       c6v0  : move c6 to c8
  >>                          c8v0  : repeat c8 times
  [
  <<<[>+>+<<-]                        c5v0  : move c5 to c6 and c7
  >>[<<+>>-]                      c7v0  : move c7 back to c5
  >-
  ]
  <<<<-                           c4    : decrement loop counter
  ]