Initial data commit

Task/Van-der-Corput-sequence/BCPL/van-der-corput-sequence.bcpl

@@ -0,0 +1,39 @@
+get "libhdr"
+
+let corput(n, base, num, denom) be
+$(  let p = 0 and q = 1
+    until n=0
+    $(  p := p * base + n rem base
+        q := q * base
+        n := n / base
+    $)
+
+    !num := p
+    !denom := q
+
+    until p=0
+    $(  n := p
+        p := q rem p
+        q := n
+    $)
+
+    !num := !num / q
+    !denom := !denom / q
+$)
+
+let writefrac(num, denom) be
+    test num=0
+        do writes("  0")
+        or writef("  %N/%N", num, denom)
+
+let start() be
+$(  let num = ? and denom = ?
+    for base=2 to 5
+    $(  writef("base %N:", base)
+        for i=0 to 9
+        $(  corput(i, base, @num, @denom)
+            writefrac(num, denom)
+        $)
+        wrch('*N')
+    $)
+$)