Commit | Line | Data |
---|---|---|
5f05dabc | 1 | #!./perl |
2 | ||
3 | # | |
4 | # test recursive functions. | |
5 | # | |
6 | ||
4fc93207 JH |
7 | BEGIN { |
8 | chdir 't' if -d 't'; | |
9 | @INC = qw(. ../lib); | |
10 | require "test.pl"; | |
b8f55b69 | 11 | plan(tests => 28); |
4fc93207 JH |
12 | } |
13 | ||
14 | use strict; | |
5f05dabc | 15 | |
4fc93207 | 16 | sub gcd { |
5f05dabc | 17 | return gcd($_[0] - $_[1], $_[1]) if ($_[0] > $_[1]); |
18 | return gcd($_[0], $_[1] - $_[0]) if ($_[0] < $_[1]); | |
19 | $_[0]; | |
20 | } | |
21 | ||
4fc93207 | 22 | sub factorial { |
5f05dabc | 23 | $_[0] < 2 ? 1 : $_[0] * factorial($_[0] - 1); |
24 | } | |
25 | ||
4fc93207 | 26 | sub fibonacci { |
5f05dabc | 27 | $_[0] < 2 ? 1 : fibonacci($_[0] - 2) + fibonacci($_[0] - 1); |
28 | } | |
29 | ||
30 | # Highly recursive, highly aggressive. | |
31 | # Kids, don't try this at home. | |
5f05dabc | 32 | # |
4fdae800 | 33 | # For example ackermann(4,1) will take quite a long time. |
34 | # It will simply eat away your memory. Trust me. | |
5f05dabc | 35 | |
4fc93207 | 36 | sub ackermann { |
5f05dabc | 37 | return $_[1] + 1 if ($_[0] == 0); |
38 | return ackermann($_[0] - 1, 1) if ($_[1] == 0); | |
39 | ackermann($_[0] - 1, ackermann($_[0], $_[1] - 1)); | |
40 | } | |
41 | ||
42 | # Highly recursive, highly boring. | |
43 | ||
4fc93207 | 44 | sub takeuchi { |
5f05dabc | 45 | $_[1] < $_[0] ? |
46 | takeuchi(takeuchi($_[0] - 1, $_[1], $_[2]), | |
47 | takeuchi($_[1] - 1, $_[2], $_[0]), | |
48 | takeuchi($_[2] - 1, $_[0], $_[1])) | |
49 | : $_[2]; | |
50 | } | |
51 | ||
6bc70b07 | 52 | is(gcd(1147, 1271), 31, "gcd(1147, 1271) == 31"); |
5f05dabc | 53 | |
6bc70b07 | 54 | is(gcd(1908, 2016), 36, "gcd(1908, 2016) == 36"); |
5f05dabc | 55 | |
6bc70b07 | 56 | is(factorial(10), 3628800, "factorial(10) == 3628800"); |
5f05dabc | 57 | |
6bc70b07 | 58 | is(factorial(factorial(3)), 720, "factorial(factorial(3)) == 720"); |
5f05dabc | 59 | |
6bc70b07 | 60 | is(fibonacci(10), 89, "fibonacci(10) == 89"); |
5f05dabc | 61 | |
6bc70b07 | 62 | is(fibonacci(fibonacci(7)), 17711, "fibonacci(fibonacci(7)) == 17711"); |
5f05dabc | 63 | |
4fc93207 | 64 | my @ack = qw(1 2 3 4 2 3 4 5 3 5 7 9 5 13 29 61); |
5f05dabc | 65 | |
4fc93207 JH |
66 | for my $x (0..3) { |
67 | for my $y (0..3) { | |
68 | my $a = ackermann($x, $y); | |
6bc70b07 | 69 | is($a, shift(@ack), "ackermann($x, $y) == $a"); |
5f05dabc | 70 | } |
71 | } | |
72 | ||
4fc93207 | 73 | my ($x, $y, $z) = (18, 12, 6); |
5f05dabc | 74 | |
4fc93207 | 75 | is(takeuchi($x, $y, $z), $z + 1, "takeuchi($x, $y, $z) == $z + 1"); |
959e3673 GS |
76 | |
77 | { | |
78 | sub get_first1 { | |
79 | get_list1(@_)->[0]; | |
80 | } | |
81 | ||
82 | sub get_list1 { | |
4fc93207 | 83 | return [curr_test] unless $_[0]; |
959e3673 GS |
84 | my $u = get_first1(0); |
85 | [$u]; | |
86 | } | |
87 | my $x = get_first1(1); | |
4fc93207 | 88 | ok($x, "premature FREETMPS (change 5699)"); |
959e3673 GS |
89 | } |
90 | ||
91 | { | |
92 | sub get_first2 { | |
93 | return get_list2(@_)->[0]; | |
94 | } | |
95 | ||
96 | sub get_list2 { | |
4fc93207 | 97 | return [curr_test] unless $_[0]; |
959e3673 GS |
98 | my $u = get_first2(0); |
99 | return [$u]; | |
100 | } | |
101 | my $x = get_first2(1); | |
4fc93207 JH |
102 | ok($x, "premature FREETMPS (change 5699)"); |
103 | } | |
104 | ||
105 | { | |
106 | local $^W = 0; # We do not need recursion depth warning. | |
107 | ||
108 | sub sillysum { | |
109 | return $_[0] + ($_[0] > 0 ? sillysum($_[0] - 1) : 0); | |
110 | } | |
111 | ||
112 | is(sillysum(1000), 1000*1001/2, "recursive sum of 1..1000"); | |
959e3673 GS |
113 | } |
114 | ||
b8f55b69 | 115 | # check ok for recursion depth > 65536 |
87569c6d JH |
116 | { |
117 | my $r; | |
118 | eval { | |
119 | $r = runperl( | |
120 | nolib => 1, | |
121 | stderr => 1, | |
122 | prog => q{$d=0; $e=1; sub c { ++$d; if ($d > 66000) { $e=0 } else { c(); c() unless $d % 32768 } --$d } c(); exit $e}); | |
123 | }; | |
124 | SKIP: { | |
125 | skip("Out of memory -- increase your data/heap?", 2) | |
d3976849 | 126 | if $r =~ /Out of memory/i; |
87569c6d | 127 | is($r, '', "64K deep recursion - no output expected"); |
7b903762 | 128 | is($?, 0, "64K deep recursion - no coredump expected"); |
87569c6d JH |
129 | } |
130 | } | |
131 |