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Commit a4c0b7f

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Upload note code of chapter 6 algorithms
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‎6_STL_algorithms/6_3_1_numeric.cpp‎

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// file: 6numeric.cpp
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#include <numeric>
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#include <vector>
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#include <functional> // minus<int>()
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#include <iostream> // ostream_iterator
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#include <iterator>
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using namespace std;
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int main() {
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int ia[5] = {1, 2, 3, 4, 5};
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vector<int> iv(ia, ia + 5);
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// 0+1+2+3...
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cout << accumulate(iv.begin(), iv.end(), 0) << endl;
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// 0-1-2-3
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cout << accumulate(iv.begin(), iv.end(), 0, minus<int>()) << endl;
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// 10 + 1*1 + 2*2 + ...
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cout << inner_product(iv.begin(), iv.end(), iv.begin(), 10) << endl;
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// 10 - 1+1 - 2+2 - ...
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cout << inner_product(iv.begin(), iv.end(), iv.begin(), 10,
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minus<int>(), plus<int>()) << endl;
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// 将迭代器绑定到cout,作为输出用
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ostream_iterator<int> oite(cout, " ");
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// 1 3 6 10 15 累计和
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partial_sum(iv.begin(), iv.end(), oite);
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cout << endl;
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// 1 -1 -4 -8 -13 累计差
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partial_sum(iv.begin(), iv.end(), oite, minus<int>());
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cout << endl;
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// 1 1 1 1 1 new #n = #n - #n-1
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adjacent_difference(iv.begin(), iv.end(), oite);
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cout << endl;
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// 1 3 5 7 9 new #n = op(#n, #n-1)
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adjacent_difference(iv.begin(), iv.end(), oite, plus<int>());
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cout << endl;
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// mingw c++ 中stl没有power实现
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// cout << power(10, 3) << endl;
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// cout << power(10, 3, plus<int>()) << endl;
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int n = 3;
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iota(iv.begin(), iv.end(), n); // 填入n, n+1, n+2
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for (int i = 0; i < iv.size(); ++i)
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cout << iv[i] << ' ';
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}

‎6_STL_algorithms/6_3_2_stl_numeric.h‎

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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996,1997
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/* NOTE: This is an internal header file, included by other STL headers.
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* You should not attempt to use it directly.
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*/
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#ifndef __SGI_STL_INTERNAL_NUMERIC_H
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#define __SGI_STL_INTERNAL_NUMERIC_H
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__STL_BEGIN_NAMESPACE
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// 必须提供init值,使得区间为空时仍能返回值
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template <class _InputIterator, class _Tp>
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_Tp accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
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{
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__STL_REQUIRES(_InputIterator, _InputIterator);
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for ( ; __first != __last; ++__first)
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__init = __init + *__first; // 将每个元素值累加
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return __init;
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}
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template <class _InputIterator, class _Tp, class _BinaryOperation>
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_Tp accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
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_BinaryOperation __binary_op)
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{
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__STL_REQUIRES(_InputIterator, _InputIterator);
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for ( ; __first != __last; ++__first)
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__init = __binary_op(__init, *__first); // 对每一个元素进行二元操作
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return __init;
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}
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template <class _InputIterator1, class _InputIterator2, class _Tp>
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_Tp inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
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_InputIterator2 __first2, _Tp __init)
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{
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__STL_REQUIRES(_InputIterator2, _InputIterator);
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__STL_REQUIRES(_InputIterator2, _InputIterator);
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// 执行两个序列的内积
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for ( ; __first1 != __last1; ++__first1, ++__first2)
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__init = __init + (*__first1 * *__first2);
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return __init;
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}
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template <class _InputIterator1, class _InputIterator2, class _Tp,
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class _BinaryOperation1, class _BinaryOperation2>
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_Tp inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
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_InputIterator2 __first2, _Tp __init,
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_BinaryOperation1 __binary_op1,
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_BinaryOperation2 __binary_op2)
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{
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__STL_REQUIRES(_InputIterator2, _InputIterator);
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__STL_REQUIRES(_InputIterator2, _InputIterator);
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// 以提供的仿函数执行两个序列运算
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for ( ; __first1 != __last1; ++__first1, ++__first2)
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__init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
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return __init;
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}
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template <class _InputIterator, class _OutputIterator, class _Tp>
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_OutputIterator
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__partial_sum(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _Tp*)
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{
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_Tp __value = *__first;
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while (++__first != __last) {
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__value = __value + *__first; // 前n项和
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*++__result = __value; // 赋值
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}
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return ++__result;
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}
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template <class _InputIterator, class _OutputIterator>
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_OutputIterator
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partial_sum(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result)
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{
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__STL_REQUIRES(_InputIterator, _InputIterator);
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__STL_REQUIRES(_OutputIterator, _OutputIterator);
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if (__first == __last) return __result;
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*__result = *__first;
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return __partial_sum(__first, __last, __result, __VALUE_TYPE(__first));
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}
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template <class _InputIterator, class _OutputIterator, class _Tp,
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class _BinaryOperation>
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_OutputIterator
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__partial_sum(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _Tp*, _BinaryOperation __binary_op)
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{
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_Tp __value = *__first;
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while (++__first != __last) {
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__value = __binary_op(__value, *__first); // 前n项运算结果
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*++__result = __value; // 赋值
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}
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return ++__result;
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}
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template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
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_OutputIterator
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partial_sum(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _BinaryOperation __binary_op)
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{
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__STL_REQUIRES(_InputIterator, _InputIterator);
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__STL_REQUIRES(_OutputIterator, _OutputIterator);
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if (__first == __last) return __result;
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*__result = *__first;
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return __partial_sum(__first, __last, __result, __VALUE_TYPE(__first),
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__binary_op);
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}
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template <class _InputIterator, class _OutputIterator, class _Tp>
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_OutputIterator
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__adjacent_difference(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _Tp*)
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{
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_Tp __value = *__first; // 记录第一个元素
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while (++__first != __last) {
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_Tp __tmp = *__first;
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*++__result = __tmp - __value; // 差值赋值
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__value = __tmp;
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}
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return ++__result;
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}
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template <class _InputIterator, class _OutputIterator>
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_OutputIterator
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adjacent_difference(_InputIterator __first,
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_InputIterator __last, _OutputIterator __result)
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{
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__STL_REQUIRES(_InputIterator, _InputIterator);
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__STL_REQUIRES(_OutputIterator, _OutputIterator);
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if (__first == __last) return __result;
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*__result = *__first;
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// 侯捷原注解:可以直接萃取类型,无需传递调用
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// iterator_traits<InputIterator>::value_type value = *first;
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// while (++__first != __last) {
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// _Tp __tmp = *__first;
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// *++__result = __tmp - __value; // 差值赋值
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// __value = __tmp;
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// }
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// return ++__result;
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return __adjacent_difference(__first, __last, __result,
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__VALUE_TYPE(__first));
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}
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template <class _InputIterator, class _OutputIterator, class _Tp,
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class _BinaryOperation>
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_OutputIterator
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__adjacent_difference(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _Tp*,
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_BinaryOperation __binary_op) {
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_Tp __value = *__first; // 记录第一个元素
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while (++__first != __last) {
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_Tp __tmp = *__first;
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*++__result = __binary_op(__tmp, __value); // 将相邻元素的运算结果赋值
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__value = __tmp;
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}
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return ++__result;
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}
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template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
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_OutputIterator
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adjacent_difference(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _BinaryOperation __binary_op)
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{
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__STL_REQUIRES(_InputIterator, _InputIterator);
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__STL_REQUIRES(_OutputIterator, _OutputIterator);
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if (__first == __last) return __result;
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*__result = *__first;
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return __adjacent_difference(__first, __last, __result,
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__VALUE_TYPE(__first),
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__binary_op);
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}
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// Returns __x ** __n, where __n >= 0. _Note that "multiplication"
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// is required to be associative, but not necessarily commutative.
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// SGI专属 power,不是标准
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// _MonoidOperation 必须满足结合律
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template <class _Tp, class _Integer, class _MonoidOperation>
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_Tp __power(_Tp __x, _Integer __n, _MonoidOperation __opr)
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{
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if (__n == 0)
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return identity_element(__opr); // 取出证同元素,见7.3节
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else {
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while ((__n & 1) == 0) {
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__n >>= 1;
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__x = __opr(__x, __x);
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}
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_Tp __result = __x;
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__n >>= 1;
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while (__n != 0) {
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__x = __opr(__x, __x);
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if ((__n & 1) != 0)
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__result = __opr(__result, __x);
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__n >>= 1;
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}
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return __result;
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}
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}
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template <class _Tp, class _Integer>
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inline _Tp __power(_Tp __x, _Integer __n)
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{
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return __power(__x, __n, multiplies<_Tp>()); // 指定为累乘
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}
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// Alias for the internal name __power. Note that power is an extension,
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// not part of the C++ standard.
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template <class _Tp, class _Integer, class _MonoidOperation>
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inline _Tp power(_Tp __x, _Integer __n, _MonoidOperation __opr)
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{
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return __power(__x, __n, __opr);
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}
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template <class _Tp, class _Integer>
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inline _Tp power(_Tp __x, _Integer __n)
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{
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return __power(__x, __n);
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}
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// iota is not part of the C++ standard. It is an extension.
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// 非标准,SGI专属,设定区间递增内容
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template <class _ForwardIter, class _Tp>
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void
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iota(_ForwardIter __first, _ForwardIter __last, _Tp __value)
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{
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__STL_REQUIRES(_ForwardIter, _Mutable_ForwardIterator);
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__STL_CONVERTIBLE(_Tp, typename iterator_traits<_ForwardIter>::value_type);
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while (__first != __last)
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*__first++ = __value++;
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}
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__STL_END_NAMESPACE
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#endif /* __SGI_STL_INTERNAL_NUMERIC_H */
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// Local Variables:
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// mode:C++
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// End:

‎6_STL_algorithms/6_4_1_algobase.cpp‎

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// file: 6algobase.cpp
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#include <algorithm>
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#include <vector>
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#include <functional>
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#include <iostream>
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#include <iterator>
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#include <string>
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using namespace std;
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template <class T>
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struct display {
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void operator() (const T& x) const {
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cout << x << ' ';
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}
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};
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int main() {
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int ia[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
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// int ib = iota(ia, ia + 9, 0); // include numeric
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vector<int> iv1(ia, ia + 5);
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vector<int> iv2(ia, ia + 9);
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// 判断两个序列第一个不匹配点 pair(第一个序列的不匹配点,第二个序列的不匹配点)
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cout << *(mismatch(iv1.begin(), iv1.end(), iv2.begin()).first);
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cout << *(mismatch(iv1.begin(), iv1.end(), iv2.begin()).second);
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// 如果序列在区间内相等,equal返回true
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cout << equal(iv1.begin(), iv1.end(), iv2.begin());
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cout << equal(iv1.begin(), iv1.end(), &ia[3]);
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cout << equal(iv1.begin(), iv1.end(), &ia[3], less<int>());
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fill(iv1.begin(), iv1.end(), 9);
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for_each(iv1.begin(), iv1.end(), display<int>());
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fill_n(iv1.begin(), 3, 7); // 从迭代器开始填3个7
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for_each(iv1.begin(), iv1.end(), display<int>());
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vector<int>::iterator ite1 = iv1.begin();
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vector<int>::iterator ite2 = ite1; // 指向7
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advance(ite2, 3); // 指向9,前进
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iter_swap(ite1, ite2);
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cout << *ite1 << ' ' << *ite2 << endl;
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for_each(iv1.begin(), iv1.end(), display<int>());
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cout << max(*ite1, *ite2) << endl;
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cout << min(*ite1, *ite2) << endl;
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// 错误写法
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cout << *max(ite1, ite2) << endl;
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cout << *min(ite1, ite2) << endl;
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swap(*iv1.begin(), *iv2.begin());
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for_each(iv1.begin(), iv1.end(), display<int>());
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for_each(iv2.begin(), iv2.end(), display<int>());
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string stra1[] = {"Jamie", "JJHou", "Jason"};
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string stra2[] = {"Jamie", "JJHou", "Jerry"};
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cout << lexicographical_compare(stra1, stra1 + 2, stra2, stra2 + 2);
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cout << lexicographical_compare(stra1, stra1 + 2, stra2, stra2 + 2,
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greater<string>());
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}

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