bc/dc: fix length(0) and length(0.000nnn) result

function                                             old     new   delta
zxc_vm_process                                      6464    6498     +34

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

testsuite/bc.tests

@@ -182,6 +182,11 @@ testing "bc print 1,2,3" \
 	"123" \
 	"" "print 1,2,3"
 
+testing "bc length" \
+	"bc" \
+	"1\n3\n1\n3\n3\n" \
+	"" "length(0); length(100); length(0.01); length(0.00120); length(0.012-0.012);"
+
 testing "bc { print 1 }" \
 	"bc" \
 	"1" \

testsuite/dc.tests

@@ -114,6 +114,11 @@ testing "dc newline can be a register" \
 	"2\n9\n" \
 	"" "[2p]s\n[3p]l\nx\n9p"
 
+testing "dc Z (length) for numbers" \
+	"dc" \
+	"1\n1\n3\n1\n3\n1\n" \
+	"" "0Zp\n0.000Zp\n100Zp\n0.01Zp\n0.00120Zp\n0.0012 0.0012 - Zp\n"
+
 for f in dc_*.dc; do
 	r="`basename "$f" .dc`_results.txt"
 	test -f "$r" || continue