Data update

Task/Totient-function/BCPL/totient-function.bcpl

@@ -0,0 +1,31 @@
+get "libhdr"
+
+let totient(n) = valof
+$(  let tot = n and i = 2
+    while i*i <= n
+    $(  if n rem i = 0
+        $(  while n rem i = 0 do n := n / i
+            tot := tot - tot/i
+        $)
+        if i=2 then i:=1
+        i := i+2
+    $)
+    resultis n>1 -> tot-tot/n, tot
+$)
+
+let start() be
+$(  let count = 0
+    writes(" N  Totient  Prime*N")
+    for n = 1 to 25
+    $(  let tot = totient(n)
+        let prime = n-1 = tot
+        if prime then count := count + 1
+        writef("%I2  %I7  %S*N", n, tot, prime -> "  Yes", "   No")
+    $)
+    writef("Number of primes up to %I6: %I4*N", 25, count)
+    for n = 26 to 10000
+    $(  if totient(n) = n-1 then count := count + 1
+        if n = 100 | n = 1000 | n = 10000 then
+            writef("Number of primes up to %I6: %I4*N", n, count)
+    $)
+$)