RosettaCodeData/Task/Damm-algorithm/Modula-2/damm-algorithm.mod2

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MODULE DammAlgorithm;
FROM FormatString IMPORT FormatString;
FROM Terminal IMPORT WriteString,WriteLn,ReadChar;
TYPE TA = ARRAY[0..9],[0..9] OF INTEGER;
CONST table = TA{
{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0}
};
PROCEDURE Damm(s : ARRAY OF CHAR) : BOOLEAN;
VAR interim,i : INTEGER;
BEGIN
interim := 0;
i := 0;
WHILE s[i] # 0C DO
interim := table[interim,INT(s[i])-INT('0')];
INC(i);
END;
RETURN interim=0;
END Damm;
PROCEDURE Print(number : INTEGER);
VAR
isValid : BOOLEAN;
buf : ARRAY[0..16] OF CHAR;
BEGIN
FormatString("%i", buf, number);
isValid := Damm(buf);
WriteString(buf);
IF isValid THEN
WriteString(" is valid");
ELSE
WriteString(" is invalid");
END;
WriteLn;
END Print;
BEGIN
Print(5724);
Print(5727);
Print(112946);
Print(112949);
ReadChar;
END DammAlgorithm.