168 lines
4.8 KiB
C++
168 lines
4.8 KiB
C++
/**************************************************************************
|
|
*
|
|
* alg6.cpp - STL generic algorithms that produce new sequences.
|
|
*
|
|
* $Id: alg6.cpp 550991 2007-06-26 23:58:07Z sebor $
|
|
*
|
|
***************************************************************************
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed
|
|
* with this work for additional information regarding copyright
|
|
* ownership. The ASF licenses this file to you under the Apache
|
|
* License, Version 2.0 (the "License"); you may not use this file
|
|
* except in compliance with the License. You may obtain a copy of
|
|
* the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
|
|
* implied. See the License for the specific language governing
|
|
* permissions and limitations under the License.
|
|
*
|
|
* Copyright 1994-2006 Rogue Wave Software.
|
|
*
|
|
**************************************************************************/
|
|
|
|
#include <vector>
|
|
#include <list>
|
|
#include <functional>
|
|
#include <algorithm>
|
|
#include <numeric>
|
|
#include <iostream>
|
|
#include <iterator>
|
|
#include <functional>
|
|
|
|
#include <examples.h>
|
|
|
|
typedef std::ostream_iterator<int, char, std::char_traits<char> > ostrm_iter_type;
|
|
|
|
|
|
int square (int n) {
|
|
return n * n;
|
|
}
|
|
|
|
|
|
class iotaGen {
|
|
public:
|
|
iotaGen (int iv) : current (iv)
|
|
{ }
|
|
int operator () () {
|
|
return current++;
|
|
}
|
|
private:
|
|
int current;
|
|
};
|
|
|
|
|
|
// Illustrate the use of the transform algorithm.
|
|
void transform_example () {
|
|
|
|
// Generate a std::list of values from 1 to 6.
|
|
std::list<int, std::allocator<int> > aList;
|
|
|
|
std::generate_n (std::inserter (aList, aList.begin ()), 6, iotaGen (1));
|
|
std::cout << "Original list: ";
|
|
std::copy (aList.begin (), aList.end (), ostrm_iter_type (std::cout, " "));
|
|
|
|
std::cout << std::endl;
|
|
|
|
// Transform elements by squaring, copy into std::vector.
|
|
std::vector<int, std::allocator<int> > aVec (6);
|
|
|
|
std::transform (aList.begin (), aList.end (), aVec.begin (), square);
|
|
std::cout << "After squaring: ";
|
|
std::copy (aVec.begin (), aVec.end (), ostrm_iter_type (std::cout, " "));
|
|
|
|
std::cout << std::endl;
|
|
|
|
// Transform std::vector again, in place, yielding 4th powers.
|
|
std::transform (aVec.begin (), aVec.end (), aVec.begin (), square);
|
|
std::cout << "After squaring again: ";
|
|
std::copy (aVec.begin (), aVec.end (),ostrm_iter_type (std::cout, " "));
|
|
|
|
std::cout << std::endl;
|
|
|
|
// Transform in parallel, yielding cubes.
|
|
std::vector<int, std::allocator<int> > cubes (6);
|
|
|
|
std::transform (aVec.begin (), aVec.end (), aList.begin (), cubes.begin (),
|
|
std::divides<int> ());
|
|
std::cout << "After division: ";
|
|
std::copy (cubes.begin (), cubes.end (), ostrm_iter_type (std::cout, " "));
|
|
|
|
std::cout << std::endl;
|
|
}
|
|
|
|
|
|
// Illustrate the use of the partial sum algorithm.
|
|
void partial_sum_example () {
|
|
|
|
// Generate values 1 to 5.
|
|
std::vector<int, std::allocator<int> > aVec (5);
|
|
std::generate (aVec.begin (), aVec.end (), iotaGen (1));
|
|
|
|
// Output partial sums.
|
|
std::cout << "Partial sums examples" << std::endl;
|
|
std::cout << "Partial sums : ";
|
|
std::partial_sum (aVec.begin (), aVec.end (),
|
|
ostrm_iter_type (std::cout, " "));
|
|
|
|
std::cout << std::endl;
|
|
|
|
// Output partial products.
|
|
std::cout << "Partial products: ";
|
|
std::partial_sum (aVec.begin (), aVec.end (),
|
|
ostrm_iter_type (std::cout, " "), std::multiplies<int> () );
|
|
|
|
std::cout << std::endl;
|
|
}
|
|
|
|
|
|
// Illustrate the use of the adjacent difference algorithm.
|
|
void adjacent_difference_example () {
|
|
|
|
// Generate values 1 to 5.
|
|
std::vector<int, std::allocator<int> > aVec (5);
|
|
std::generate (aVec.begin (), aVec.end (), iotaGen (1));
|
|
|
|
// Output partial sums.
|
|
std::cout << "Adjacent Differences examples" << std::endl;
|
|
std::cout << "Adjacent Differences : ";
|
|
std::adjacent_difference
|
|
(aVec.begin (), aVec.end (), ostrm_iter_type (std::cout, " "));
|
|
std::cout << std::endl;
|
|
|
|
// Output partial products.
|
|
std::cout << "Adjacent sums: ";
|
|
std::adjacent_difference (aVec.begin (), aVec.end (),
|
|
ostrm_iter_type (std::cout, " "),
|
|
std::plus<int> ());
|
|
|
|
std::cout << std::endl;
|
|
}
|
|
|
|
|
|
int main () {
|
|
|
|
std::cout << "STL generic algorithms -- that transform sequences"
|
|
<< std::endl;
|
|
|
|
transform_example ();
|
|
partial_sum_example ();
|
|
adjacent_difference_example ();
|
|
|
|
std::cout << "End generic transform algorithms example" << std::endl;
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|