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- // -- control_structures.cpp -- The Boost Lambda Library ------------------
- //
- // Copyright (C) 2000-2003 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
- // Copyright (C) 2000-2003 Gary Powell (powellg@amazon.com)
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- //
- // For more information, see www.boost.org
- // -----------------------------------------------------------------------
- #include <boost/test/minimal.hpp> // see "Header Implementation Option"
- #include "boost/lambda/lambda.hpp"
- #include "boost/lambda/if.hpp"
- #include "boost/lambda/loops.hpp"
- #include <iostream>
- #include <algorithm>
- #include <vector>
- using namespace boost;
- using boost::lambda::constant;
- using boost::lambda::_1;
- using boost::lambda::_2;
- using boost::lambda::_3;
- using boost::lambda::make_const;
- using boost::lambda::for_loop;
- using boost::lambda::while_loop;
- using boost::lambda::do_while_loop;
- using boost::lambda::if_then;
- using boost::lambda::if_then_else;
- using boost::lambda::if_then_else_return;
- // 2 container for_each
- template <class InputIter1, class InputIter2, class Function>
- Function for_each(InputIter1 first, InputIter1 last,
- InputIter2 first2, Function f) {
- for ( ; first != last; ++first, ++first2)
- f(*first, *first2);
- return f;
- }
- void simple_loops() {
- // for loops ---------------------------------------------------------
- int i;
- int arithmetic_series = 0;
- for_loop(_1 = 0, _1 < 10, _1++, arithmetic_series += _1)(i);
- BOOST_CHECK(arithmetic_series == 45);
- // no body case
- for_loop(boost::lambda::var(i) = 0, boost::lambda::var(i) < 100, ++boost::lambda::var(i))();
- BOOST_CHECK(i == 100);
-
- // while loops -------------------------------------------------------
- int a = 0, b = 0, c = 0;
- while_loop((_1 + _2) >= (_1 * _2), (++_1, ++_2, ++_3))(a, b, c);
- BOOST_CHECK(c == 3);
- int count;
- count = 0; i = 0;
- while_loop(_1++ < 10, ++boost::lambda::var(count))(i);
- BOOST_CHECK(count == 10);
- // note that the first parameter of do_while_loop is the condition
- count = 0; i = 0;
- do_while_loop(_1++ < 10, ++boost::lambda::var(count))(i);
- BOOST_CHECK(count == 11);
- a = 0;
- do_while_loop(constant(false), _1++)(a);
- BOOST_CHECK(a == 1);
-
- // no body cases
- a = 40; b = 30;
- while_loop(--_1 > _2)(a, b);
- BOOST_CHECK(a == b);
- // (the no body case for do_while_loop is pretty redundant)
- a = 40; b = 30;
- do_while_loop(--_1 > _2)(a, b);
- BOOST_CHECK(a == b);
- }
- void simple_ifs () {
- int value = 42;
- if_then(_1 < 0, _1 = 0)(value);
- BOOST_CHECK(value == 42);
- value = -42;
- if_then(_1 < 0, _1 = -_1)(value);
- BOOST_CHECK(value == 42);
- int min;
- if_then_else(_1 < _2, boost::lambda::var(min) = _1, boost::lambda::var(min) = _2)
- (make_const(1), make_const(2));
- BOOST_CHECK(min == 1);
- if_then_else(_1 < _2, boost::lambda::var(min) = _1, boost::lambda::var(min) = _2)
- (make_const(5), make_const(3));
- BOOST_CHECK(min == 3);
- int x, y;
- x = -1; y = 1;
- BOOST_CHECK(if_then_else_return(_1 < _2, _2, _1)(x, y) == (std::max)(x ,y));
- BOOST_CHECK(if_then_else_return(_1 < _2, _2, _1)(y, x) == (std::max)(x ,y));
- }
- int test_main(int, char *[])
- {
- simple_loops();
- simple_ifs();
- return 0;
- }
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