Upload note code of chapter 8 adpater

Author: SilverMaple

8_STL_adapter/8_1_2_iterator-adapter.cpp

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+// file: 8iterator-adapter.cpp
+
+#include <iterator> // for iterator adapters
+#include <deque>
+#include <algorithm> // for copy()
+#include <iostream>
+
+using namespace std;
+
+int main() {
+    // 将outite绑定到cout，每次对outite指派一个元素，就后接一个“ ”
+    ostream_iterator<int> outite(cout, " ");
+
+    int ia[] = {0, 1, 2, 3, 4, 5};
+    deque<int> id(ia, ia + 6);
+
+    // 将所有元素拷贝到outite，即cout
+    copy(id.begin(), id.end(), outite);
+    cout << endl;
+
+    // 将ia[]的部分元素拷贝到id内，使用front_insert_iterator
+    // front_insert_iterator会将assign操作给push_front操作
+    // vector不支持push_front操作，所以不以vector做示范对象
+    copy(ia + 1, ia + 2, front_inserter(id));
+    copy(id.begin(), id.end(), outite);
+    cout << endl;
+
+    // 将ia[]的部分元素拷贝到id内，使用back_insert_iterator
+    copy(ia + 1, ia + 2, back_inserter(id));
+    copy(id.begin(), id.end(), outite);
+    cout << endl;
+
+    // 搜寻元素5所在位置
+    deque<int>::iterator ite = find(id.begin(), id.end(), 5);
+    // 将ia[]的部分元素拷贝到id内，使用insert_iterator
+    copy(ia + 1, ia + 2, inserter(id, ite));
+    copy(id.begin(), id.end(), outite);
+    cout << endl;
+
+    // 将所有元素逆向拷贝到outite
+    // rbegin()和rend()与reverse_iterator有关
+    copy(id.rbegin(), id.rend(), outite);
+    cout << endl;
+
+    // 将inite绑定到cin，将元素拷贝到inite，知道eos出现
+    istream_iterator<int> inite(cin), eos; // eos: end-of-stream
+    copy(inite, eos, inserter(id, id.begin()));
+    // 输入数字，停止时可以输入任意字符
+
+    copy(id.begin(), id.end(), outite);
+}

8_STL_adapter/8_1_3_compose.cpp

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+// file: 8compose.cpp
+
+#include <algorithm>
+#include <functional>
+#include <vector>
+#include <iostream>
+#include <iterator>
+
+using namespace std;
+
+// compose1在mingw中没有，所以把定义搬了过来
+template <class _Operation1, class _Operation2>
+class unary_compose
+  : public unary_function<typename _Operation2::argument_type,
+                          typename _Operation1::result_type> 
+{
+protected:
+  _Operation1 _M_fn1;
+  _Operation2 _M_fn2;
+public:
+  unary_compose(const _Operation1& __x, const _Operation2& __y) 
+    : _M_fn1(__x), _M_fn2(__y) {}
+  typename _Operation1::result_type
+  operator()(const typename _Operation2::argument_type& __x) const {
+    return _M_fn1(_M_fn2(__x));
+  }
+};
+
+template <class _Operation1, class _Operation2>
+inline unary_compose<_Operation1,_Operation2> 
+compose1(const _Operation1& __fn1, const _Operation2& __fn2)
+{
+  return unary_compose<_Operation1,_Operation2>(__fn1, __fn2);
+}
+
+int main() {
+    // 将outite绑定到cout，每次对outite指派一个元素，就后接一个“ ”
+    ostream_iterator<int> outite(cout, " ");
+
+    int ia[6] = {2, 21, 12, 7, 19, 23};
+    vector<int> iv(ia, ia + 6);
+
+    // 想执行v = (v+2)*3
+    // for_each是non-mutating algorithm，元素内容不能更改
+    // 所以执行后iv内容不变
+    for_each(iv.begin(), iv.end(),
+             compose1(bind2nd(multiplies<int>(), 3),
+                      bind2nd(plus<int>(), 2)));
+    copy(iv.begin(), iv.end(), outite);
+    cout << endl;
+
+    transform(iv.begin(), iv.end(), outite,
+             compose1(bind2nd(multiplies<int>(), 3),
+                      bind2nd(plus<int>(), 2)));
+    cout << endl;
+}

8_STL_adapter/8_1_3_functor-adapter.cpp

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+// file: 8functor-adapter.cpp
+
+#include <algorithm>
+#include <functional>
+#include <vector>
+#include <iostream>
+#include <iterator>
+
+using namespace std;
+
+// compose1在mingw中没有，所以把定义搬了过来
+template <class _Operation1, class _Operation2>
+class unary_compose
+  : public unary_function<typename _Operation2::argument_type,
+                          typename _Operation1::result_type> 
+{
+protected:
+  _Operation1 _M_fn1;
+  _Operation2 _M_fn2;
+public:
+  unary_compose(const _Operation1& __x, const _Operation2& __y) 
+    : _M_fn1(__x), _M_fn2(__y) {}
+  typename _Operation1::result_type
+  operator()(const typename _Operation2::argument_type& __x) const {
+    return _M_fn1(_M_fn2(__x));
+  }
+};
+
+template <class _Operation1, class _Operation2>
+inline unary_compose<_Operation1,_Operation2> 
+compose1(const _Operation1& __fn1, const _Operation2& __fn2)
+{
+  return unary_compose<_Operation1,_Operation2>(__fn1, __fn2);
+}
+
+
+void print(int i) {
+    cout << i << " ";
+}
+
+class Int {
+public: 
+    // explicit 只能修改只有一个参数的类构造函数，
+    // 或是除了第一个参数外其他参数都有默认值的情况
+    // 表明该构造函数是显示的而非隐式的
+    // 作用是禁止类构造函数的隐式自动转换
+    // implicit 表示隐式，类构造函数默认声明为隐式
+    // google c++规范与effective c++都推荐使用explicit声明
+    explicit Int(int i) : m_i(i) {}
+
+    void print1() const {
+        cout << "[" << m_i << "]";
+    }
+
+private:
+    int m_i;
+};
+
+int main() {
+    // 将outite绑定到cout，每次对outite指派一个元素，就后接一个“ ”
+    ostream_iterator<int> outite(cout, " ");
+
+    int ia[6] = {2, 21, 12, 7, 19, 23};
+    vector<int> iv(ia, ia + 6);
+
+    // 找出不小于12的元素个数
+    cout << count_if(iv.begin(), iv.end(),
+                     not1(bind2nd(less<int>(), 12)));
+    cout << endl;
+
+    // 令每个元素v执行(v+2)*3然后输往outite
+    transform(iv.begin(), iv.end(), outite,
+              compose1(bind2nd(multiplies<int>(), 3),
+                       bind2nd(plus<int>(), 2)));
+    cout << endl;
+
+    // 将所有元素拷贝到outite
+    copy(iv.begin(), iv.end(), outite);
+    cout << endl;
+    // 1. 使用函数指针搭配stl算法
+    for_each(iv.begin(), iv.end(), print);
+    cout << endl;
+
+    // 2. 以修饰过的一般函数搭配stl算法
+    for_each(iv.begin(), iv.end(), ptr_fun(print));
+    cout << endl;
+
+    Int t1(3), t2(7), t3(20), t4(14), t5(68);
+    vector<Int> Iv;
+    Iv.push_back(t1);
+    Iv.push_back(t2);
+    Iv.push_back(t3);
+    Iv.push_back(t4);
+    Iv.push_back(t5);
+    // 3. 以修饰过的成员函数搭配stl算法
+    for_each(Iv.begin(), Iv.end(), mem_fun_ref(&Int::print1));
+}