Data commit

Task/Perfect-numbers/Modula-2/perfect-numbers.mod2

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+MODULE PerfectNumbers;
+
+FROM SWholeIO IMPORT
+  WriteCard;
+FROM STextIO IMPORT
+  WriteLn;
+FROM RealMath IMPORT
+  sqrt;
+
+VAR
+  N: CARDINAL;
+
+PROCEDURE IsPerfect(N: CARDINAL): BOOLEAN;
+VAR
+  S, I: CARDINAL;
+  SqrtN: REAL;
+BEGIN
+  S := 1;
+  SqrtN := sqrt(FLOAT(N));
+  IF N REM 2 = 0 THEN
+    S := S + 2 + N / 2;
+  END;
+  I := 3;
+  WHILE FLOAT(I) <= SqrtN - 1.0 DO
+    IF N REM I = 0 THEN
+      S := S + I + N / I;
+    END;
+    I := I + 1;
+  END;
+  IF I * I = N THEN
+    S := S + I;
+  END;
+  RETURN (N = S);
+END IsPerfect;
+
+BEGIN
+  FOR N := 2 TO 10000 BY 2 DO
+    IF IsPerfect(N) THEN
+      WriteCard(N, 5);
+      WriteLn;
+    END;
+  END;
+END PerfectNumbers.