Prequel
primitive recursive driven programming

Ackermann

Enter two non-negative integer numbers.
(Note that the Ackermann function grows very rapidly, even for small inputs.)

A( , ) =

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Runtime Error: DIVISION BY ZERO

←0
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←0 ← calls
← instructions
← memory (max use: 0)

Prequel program

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Parser Error: UNEXPECTED CHAR

Module: ackermann

 if ackermann is undefined 
  ackermann = [ackermann.input] 
 endif 
 m_n = ackermann.pop() 
 if m_n[0] == 0 
  if ackermann.length() == 0 
   ackermann.return(m_n[1]+1) 
  endif 
  prev_m_n = ackermann.pop() 
  prev_m_n.push(m_n[1]+1) 
  ackermann.push(prev_m_n) 
 elif m_n[1] == 0 
  m_n[0] -= 1 
  m_n[1] = 1 
  ackermann.push(m_n) 
 else 
  ackermann.push([m_n[0]-1]) 
  m_n[1] -= 1 
  ackermann.push(m_n) 
 endif

Input:

 ackermann.input 
  The list of values written in the editable text input. 
  -> e.g. [3, 2]

Functions:

 ackermann.return(result) 
  End computation and show the calculated value. 
  -> result: calculated integer value