tasks a-s

Task/Roman-numerals-Encode/ALGOL-W/roman-numerals-encode.alg

@@ -0,0 +1,51 @@
+BEGIN
+
+PROCEDURE ROMAN (INTEGER VALUE NUMBER; STRING(15) RESULT CHARACTERS; INTEGER RESULT LENGTH);
+    COMMENT
+         Returns the Roman number of an integer between 1 and 3999.
+         "MMMDCCCLXXXVIII" (15 characters long) is the longest Roman number under 4000;
+    BEGIN
+        INTEGER PLACE, POWER;
+
+        PROCEDURE APPEND (STRING(1) VALUE C);
+            BEGIN CHARACTERS(LENGTH|1) := C; LENGTH := LENGTH + 1 END;
+
+        PROCEDURE I; APPEND(CASE PLACE OF ("I","X","C","M"));
+        PROCEDURE V; APPEND(CASE PLACE OF ("V","L","D"));
+        PROCEDURE X; APPEND(CASE PLACE OF ("X","C","M"));
+
+        ASSERT (NUMBER >= 1) AND (NUMBER < 4000);
+
+        CHARACTERS := "               ";
+        LENGTH := 0;
+        POWER := 1000;
+        PLACE := 4;
+        WHILE PLACE > 0 DO
+            BEGIN
+                CASE NUMBER DIV POWER + 1 OF BEGIN
+                    BEGIN            END;
+                    BEGIN I          END;
+                    BEGIN I; I       END;
+                    BEGIN I; I; I    END;
+                    BEGIN I; V       END;
+                    BEGIN V          END;
+                    BEGIN V; I       END;
+                    BEGIN V; I; I    END;
+                    BEGIN V; I; I; I END;
+                    BEGIN I; X       END
+                END;
+                NUMBER := NUMBER REM POWER;
+                POWER := POWER DIV 10;
+                PLACE := PLACE - 1
+            END
+    END ROMAN;
+
+INTEGER I;
+STRING(15) S;
+
+ROMAN(1, S, I);    WRITE(S, I);
+ROMAN(3999, S, I); WRITE(S, I);
+ROMAN(3888, S, I); WRITE(S, I);
+ROMAN(2009, S, I); WRITE(S, I);
+ROMAN(405, S, I);  WRITE(S, I);
+END.