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1 | // -*- C++ -*- |
2 | ||
a945c346 | 3 | // Copyright (C) 2005-2024 Free Software Foundation, Inc. |
4569a895 AT |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the terms | |
7 | // of the GNU General Public License as published by the Free Software | |
748086b7 | 8 | // Foundation; either version 3, or (at your option) any later |
4569a895 AT |
9 | // version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, but | |
12 | // WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | // General Public License for more details. | |
15 | ||
16 | // You should have received a copy of the GNU General Public License | |
748086b7 JJ |
17 | // along with this library; see the file COPYING3. If not see |
18 | // <http://www.gnu.org/licenses/>. | |
19 | ||
4569a895 AT |
20 | |
21 | // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. | |
22 | ||
23 | // Permission to use, copy, modify, sell, and distribute this software | |
24 | // is hereby granted without fee, provided that the above copyright | |
25 | // notice appears in all copies, and that both that copyright notice | |
26 | // and this permission notice appear in supporting documentation. None | |
27 | // of the above authors, nor IBM Haifa Research Laboratories, make any | |
28 | // representation about the suitability of this software for any | |
29 | // purpose. It is provided "as is" without express or implied | |
30 | // warranty. | |
31 | ||
32 | /** | |
33 | * @file erase_if_example.cpp | |
34 | * A basic example showing how to use erase_if. | |
35 | */ | |
36 | ||
37 | /** | |
38 | * The following example shows how to use a conditional-erase | |
39 | * method of associative containers to erase some of their entries. | |
40 | */ | |
41 | ||
42 | #include <iostream> | |
43 | #include <cassert> | |
44 | #include <ext/pb_ds/assoc_container.hpp> | |
45 | ||
46 | using namespace std; | |
5e11f978 | 47 | using namespace __gnu_pbds; |
4569a895 AT |
48 | |
49 | // The following functor takes a map's value-type object and returns | |
50 | // whether its key is between two numbers. | |
e3869a48 | 51 | struct between |
4569a895 AT |
52 | { |
53 | // Constructor taking two numbers determining a range. | |
54 | between(int b, int e) : m_b(b), m_e(e) | |
55 | { assert(m_b < m_e); } | |
56 | ||
57 | // Operator determining whether a value-type object's key is within | |
58 | // the range. | |
e3869a48 | 59 | bool |
4569a895 AT |
60 | operator()(const pair<const int, char>& r_val) |
61 | { return r_val.first >= m_b&& r_val.first < m_e; } | |
62 | ||
63 | private: | |
64 | const int m_b; | |
65 | const int m_e; | |
66 | }; | |
67 | ||
68 | /** | |
69 | * The following function performs a sequence of operations on an | |
70 | * associative container object mapping integers to characters. Specifically | |
71 | * it inserts 100 values and then uses a conditional-erase method to erase | |
72 | * the values whose key is between 10 and 90. | |
73 | */ | |
74 | template<class Cntnr> | |
75 | void | |
76 | some_op_sequence(Cntnr r_c) | |
77 | { | |
78 | assert(r_c.empty()); | |
79 | assert(r_c.size() == 0); | |
80 | ||
81 | for (int i = 0; i < 100; ++i) | |
82 | r_c.insert(make_pair(i, static_cast<char>(i))); | |
83 | assert(r_c.size() == 100); | |
84 | ||
85 | // Erase all values whose key is between 10 (inclusive) and 90 | |
86 | // (non-inclusive). | |
87 | r_c.erase_if(between(10 , 90)); | |
88 | ||
89 | assert(!r_c.empty()); | |
90 | assert(r_c.size() == 20); | |
91 | } | |
92 | ||
93 | int main() | |
94 | { | |
95 | // Perform operations on a list-update set. | |
96 | some_op_sequence(list_update<int, char>()); | |
97 | ||
98 | // Perform operations on a collision-chaining hash set. | |
99 | some_op_sequence(cc_hash_table<int, char>()); | |
100 | ||
101 | // Perform operations on a general-probing hash set. | |
102 | some_op_sequence(gp_hash_table<int, char>()); | |
103 | ||
104 | // Perform operations on a red-black tree set. | |
105 | some_op_sequence(tree<int, char>()); | |
106 | ||
107 | // Perform operations on a splay tree set. | |
108 | some_op_sequence(tree< | |
109 | int, | |
110 | char, | |
111 | less<int>, | |
112 | splay_tree_tag>()); | |
113 | ||
114 | // Perform operations on a splay tree set. | |
115 | some_op_sequence(tree< | |
116 | int, | |
117 | char, | |
118 | less<int>, | |
119 | ov_tree_tag>()); | |
120 | ||
121 | return 0; | |
122 | } |