June 2018 Update

Task/Self-describing-numbers/Modula-2/self-describing-numbers.mod2

@@ -0,0 +1,51 @@
+MODULE SelfDescribingNumber;
+
+FROM WholeStr IMPORT
+  CardToStr;
+FROM STextIO IMPORT
+  WriteString, WriteLn;
+FROM SWholeIO IMPORT
+  WriteCard;
+
+PROCEDURE Check(Number: CARDINAL): BOOLEAN;
+VAR
+  I, D: CARDINAL;
+  A: ARRAY [0 .. 9] OF CHAR;
+  Count, W: ARRAY [0 .. 9] OF CARDINAL;
+  Result: BOOLEAN;
+BEGIN
+  CardToStr(Number, A);
+  FOR I := 0 TO 9 DO
+    Count[I] := 0;
+    W[I] := 0;
+  END;
+  FOR I := 0 TO LENGTH(A) - 1 DO
+    D := ORD(A[I]) - ORD("0");
+    INC(Count[D]);
+    W[I] := D;
+  END;
+  Result := TRUE;
+  I := 0;
+  WHILE Result AND (I <= 9) DO
+    Result := (Count[I] = W[I]);
+    INC(I);
+  END;
+  RETURN Result;
+END Check;
+
+VAR
+  X: CARDINAL;
+
+BEGIN
+  WriteString("Autodescriptive numbers from 1 to 100000000:");
+  WriteLn;
+  FOR X := 1 TO 100000000 DO
+    IF Check(X) THEN
+      WriteString(" ");
+      WriteCard(X, 1);
+      WriteLn;
+    END;
+  END;
+  WriteString("Job done.");
+  WriteLn;
+END SelfDescribingNumber.