Ackermann function: Difference between revisions

=={{header|Pascal}}==

<syntaxhighlight lang="pascal">Program Ackerman;

function ackermann(m, n: Integer) : Integer;

begin

if m = 0 then

ackermann := n+1

else if n = 0 then

ackermann := ackermann(m-1, 1)

else

ackermann := ackermann(m-1, ackermann(m, n-1));

end;

var

m, n : Integer;

begin

for n := 0 to 6 do

for m := 0 to 3 do

WriteLn('A(', m, ',', n, ') = ', ackermann(m,n));

end.</syntaxhighlight>

=={{header|PascalABC.NET}}==

<syntaxhighlight lang="delphi">

function Ackermann(m,n: integer): integer;

begin

if (m < 0) or (n < 0) then

raise new System.ArgumentOutOfRangeException();

if m = 0 then

Result := n + 1

else if n = 0 then

Result := Ackermann(m - 1, 1)

else Result := Ackermann(m - 1, Ackermann(m, n - 1))

end;

begin

for var m := 0 to 3 do

for var n := 0 to 4 do

Println($'Ackermann({m}, {n}) = {Ackermann(m,n)}');

end.

</syntaxhighlight>

{{out}}

<pre>

Ackermann(0, 0) = 1

Ackermann(0, 1) = 2

Ackermann(0, 2) = 3

Ackermann(0, 3) = 4

Ackermann(0, 4) = 5

Ackermann(1, 0) = 2

Ackermann(1, 1) = 3

Ackermann(1, 2) = 4

Ackermann(1, 3) = 5

Ackermann(1, 4) = 6

Ackermann(2, 0) = 3

Ackermann(2, 1) = 5

Ackermann(2, 2) = 7

Ackermann(2, 3) = 9

Ackermann(2, 4) = 11

Ackermann(3, 0) = 5

Ackermann(3, 1) = 13

Ackermann(3, 2) = 29

Ackermann(3, 3) = 61

Ackermann(3, 4) = 125

</pre>