Dutch national flag problem: Difference between revisions

</pre>

=={{header|Action!}}==

{{libheader|Action! Tool Kit}}

<lang Action!>INCLUDE "D2:SORT.ACT" ;from the Action! Tool Kit

PROC PrintArray(BYTE ARRAY a BYTE len)

CHAR ARRAY colors(3)=['R 'W 'B]

BYTE i,index

FOR i=0 TO len-1

DO

index=a(i)

Put(colors(index))

OD

RETURN

BYTE FUNC IsSorted(BYTE ARRAY a BYTE len)

BYTE i

IF len<=1 THEN

RETURN (1)

FI

FOR i=0 TO len-2

DO

IF a(i)>a(i+1) THEN

RETURN (0)

FI

OD

RETURN (1)

PROC Randomize(BYTE ARRAY a BYTE len)

BYTE i

FOR i=0 TO len-1

DO

a(i)=Rand(3)

OD

RETURN

PROC Main()

DEFINE SIZE="30"

BYTE ARRAY a(SIZE)

Put(125) PutE() ;clear the screen

DO

Randomize(a,SIZE)

UNTIL IsSorted(a,SIZE)=0

OD

PrintE("Unsorted:") PrintArray(a,SIZE)

PutE() PutE()

SortB(a,SIZE,0)

PrintE("Sorted:") PrintArray(a,SIZE)

PutE() PutE()

IF IsSorted(a,SIZE) THEN

PrintE("Sorting is valid")

ELSE

PrintE("Sorting is invalid!")

FI

RETURN</lang>

{{out}}

[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Dutch_national_flag_problem.png Screenshot from Atari 8-bit computer]

<pre>

Unsorted:

RBWBWRRRRRWBWRWRRBBWBBBRRWWRRR

Sorted:

RRRRRRRRRRRRRRWWWWWWWWBBBBBBBB

Sorting is valid