[faq] 解释范围、迭代器和算法

docs/_static/links.rst

@@ -21,6 +21,7 @@
 .. _`cppreference: string`: https://zh.cppreference.com/w/cpp/string/basic_string#.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0
 .. _`cppreference: vector`: https://zh.cppreference.com/w/cpp/container/vector#.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0
 .. _`cppreference: array`: https://zh.cppreference.com/w/cpp/container/array#.E6.88.90.E5.91.98.E5.87.BD.E6.95.B0
+.. _`cppreference: algorithm`: https://zh.cppreference.com/w/cpp/header/algorithm
 
 .. _`《人的正确思想是从哪里来的？》`: https://zhuanlan.zhihu.com/p/467228101
 .. _`《实践论》`: https://www.marxists.org/chinese/maozedong/marxist.org-chinese-mao-193707.htm

docs/faq/range_iterator_and_algorithm/cin_iterator.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+using namespace std;
+
+template <typename T>
+class Cin_iterator {
+ public:
+  Cin_iterator(bool is_end) : value_() {
+    if (!is_end) {
+      cin >> value_;
+    }
+  }
+
+  friend bool operator==(Cin_iterator const&, Cin_iterator const&) {
+    return cin.fail();
+  }
+  friend bool operator!=(Cin_iterator const& lhs, Cin_iterator const& rhs) {
+    return !(lhs == rhs);
+  }
+
+  T const& operator*() const {
+    return value_;
+  }
+
+  Cin_iterator& operator++() {
+    cin >> value_;
+    return *this;
+  }
+
+ private:
+  T value_;
+};

docs/faq/range_iterator_and_algorithm/forward_list_iterator.cpp

@@ -0,0 +1,25 @@
+class Forward_list_iterator {
+ public:
+  Forward_list_iterator(Node const* node) : node_(node) {}
+
+  friend bool operator==(Forward_list_iterator const& lhs,
+                         Forward_list_iterator const& rhs) {
+    return lhs.node_ == rhs.node_;
+  }
+  friend bool operator!=(Forward_list_iterator const& lhs,
+                         Forward_list_iterator const& rhs) {
+    return !(lhs == rhs);
+  }
+
+  int const& operator*() const {
+    return node_->value;
+  }
+
+  Forward_list_iterator& operator++() {
+    node_ = node_->next;
+    return *this;
+  }
+
+ private:
+  Node const* node_;
+};

docs/faq/range_iterator_and_algorithm/forward_list_iterator_simplified.cpp

@@ -0,0 +1,21 @@
+class Forward_list_iterator {
+ public:
+  Forward_list_iterator(Node const* node);
+
+  friend bool operator==(Forward_list_iterator const& lhs,
+                         Forward_list_iterator const& rhs);
+  friend bool operator!=(Forward_list_iterator const& lhs,
+                         Forward_list_iterator const& rhs);
+
+  int const& operator*() const {
+    return node_->value;
+  }
+
+  Forward_list_iterator& operator++() {
+    node_ = node_->next;
+    return *this;
+  }
+
+ private:
+  Node const* node_;
+};

docs/faq/range_iterator_and_algorithm/forward_list_node.cpp

@@ -0,0 +1,5 @@
+struct Node {
+ public:
+  int value;
+  Node* next;
+};

docs/faq/range_iterator_and_algorithm/input_iterator.cpp

@@ -0,0 +1,26 @@
+class Iter {
+ public:
+  Iter(int const* pointer) : pointer_(pointer) {}
+  // Iter(Iter const&);  // 隐式生成的拷贝函数即可满足需要
+
+  friend bool operator==(Iter const& lhs,
+                         Iter const& rhs) {  // iter == end
+    return lhs.pointer_ == rhs.pointer_;
+  }
+  friend bool operator!=(Iter const& lhs,
+                         Iter const& rhs) {  // iter != end
+    return !(lhs == rhs);
+  }
+
+  int const& operator*() const {  // *iter
+    return *pointer_;
+  }
+
+  Iter& operator++() {  // ++iter
+    ++pointer_;
+    return *this;
+  }
+
+ private:
+  int const* pointer_;
+};