June 2018 Update

Task/Van-der-Corput-sequence/Modula-2/van-der-corput-sequence.mod2

@@ -0,0 +1,50 @@
+MODULE Sequence;
+FROM FormatString IMPORT FormatString;
+FROM Terminal IMPORT WriteString,WriteLn,ReadChar;
+
+PROCEDURE vc(n,base : INTEGER; VAR num,denom : INTEGER);
+VAR p,q : INTEGER;
+BEGIN
+    p := 0;
+    q := 1;
+
+    WHILE n#0 DO
+        p := p * base + (n MOD base);
+        q := q * base;
+        n := n DIV base
+    END;
+
+    num := p;
+    denom := q;
+
+    WHILE p#0 DO
+        n := p;
+        p := q MOD p;
+        q := n
+    END;
+
+    num := num DIV q;
+    denom := denom DIV q
+END vc;
+
+VAR
+    buf : ARRAY[0..31] OF CHAR;
+    d,n,i,b : INTEGER;
+BEGIN
+    FOR b:=2 TO 5 DO
+        FormatString("base %i:", buf, b);
+        WriteString(buf);
+        FOR i:=0 TO 9 DO
+            vc(i,b,n,d);
+            IF n#0 THEN
+                FormatString("  %i/%i", buf, n, d);
+                WriteString(buf)
+            ELSE
+                WriteString("  0")
+            END
+        END;
+        WriteLn
+    END;
+
+    ReadChar
+END Sequence.