Cartesian product of two or more lists: Difference between revisions

=={{header|Modula-2}}==

<lang modula2>MODULE CartesianProduct;

FROM FormatString IMPORT FormatString;

FROM Terminal IMPORT WriteString,WriteLn,ReadChar;

PROCEDURE WriteInt(a : INTEGER);

VAR buf : ARRAY[0..9] OF CHAR;

BEGIN

FormatString("%i", buf, a);

WriteString(buf)

END WriteInt;

PROCEDURE Cartesian(a,b : ARRAY OF INTEGER);

VAR i,j : CARDINAL;

BEGIN

WriteString("[");

FOR i:=0 TO HIGH(a) DO

FOR j:=0 TO HIGH(b) DO

IF (i>0) OR (j>0) THEN

WriteString(",");

END;

WriteString("[");

WriteInt(a[i]);

WriteString(",");

WriteInt(b[j]);

WriteString("]")

END

END;

WriteString("]");

WriteLn

END Cartesian;

TYPE

AP = ARRAY[0..1] OF INTEGER;

E = ARRAY[0..0] OF INTEGER;

VAR

a,b : AP;

BEGIN

a := AP{1,2};

b := AP{3,4};

Cartesian(a,b);

a := AP{3,4};

b := AP{1,2};

Cartesian(a,b);

(* If there is a way to create an empty array, I do not know of it *)

ReadChar

END CartesianProduct.</lang>