update

README.md

@@ -163,7 +163,33 @@ for(decl:col) {
 
 - [C++中如何将string类型转换为int类型？](./basic_content/extent/string_int.md)
 
-### 5.代码运行
+### 5.自己写的工具
+
+- [容器快捷输出工具](./tool/output)
+
+对吴老师的代码进行了修改，[点击此处直通代码](./tool/output/output_container.h)
+
+输入：
+
+```cpp
+map<int, int> mp{
+            {1, 1},
+            {2, 4},
+            {3, 9}};
+    cout << mp << endl;
+```
+
+输出结果显示：
+
+```cpp
+{ 1 => 1, 2 => 4, 3 => 9 }
+```
+
+感谢吴老师的代码，原代码：
+
+> https://github.com/adah1972/output_container/blob/master/output_container.h
+
+### 6.代码运行
 
 - **代码环境**
 
@@ -173,7 +199,7 @@ Ubuntu 18.04
 
 CLion  gcc/g++
 
-### 6.关于作者
+### 7.关于作者
 
 个人公众号：
 

tool/output/container.cpp

@@ -0,0 +1,43 @@
+//
+// Created by light on 19-12-16.
+//
+
+#include <iostream>
+#include <map>
+#include <set>
+#include <vector>
+#include "output_container.h"
+
+
+using namespace std;
+
+int main() {
+    map<int, int> mp{
+            {1, 1},
+            {2, 4},
+            {3, 9}};
+    cout << mp << endl;
+    vector<vector<int>> vv{
+            {1, 1},
+            {2, 4},
+            {3, 9}};
+    cout << vv << endl;
+
+    pair<int, int> p{1, 2};
+    cout << p << endl;
+
+    set<int> s{1, 2, 3};
+    cout << s << endl;
+
+    vector<char> v{'a', 'b'};
+    cout << v << endl;
+    set<char *> vs{"a", "b"};
+    cout << vs << endl;
+
+    map<int, char *> mm{
+            {1,   "23"},
+            {2, "234hi"}
+    };
+    cout << mm << endl;
+
+}

tool/output/output_container.h

@@ -0,0 +1,150 @@
+//
+// Created by light on 20-1-8.
+//
+
+#ifndef MORDEN_C_OUTPUT_CONTAINER_H
+#define MORDEN_C_OUTPUT_CONTAINER_H
+
+#include <ostream>      // std::ostream
+#include <type_traits>  // std::false_type/true_type/decay_t/is_same_v
+#include <utility>      // std::declval/pair
+
+// 检测是否是pair
+template<typename T>
+struct is_pair : std::false_type {
+};
+template<typename T, typename U>
+struct is_pair<std::pair<T, U>> : std::true_type {
+};
+template<typename T>
+inline constexpr bool is_pair_v = is_pair<T>::value;
+
+// 检测输出函数是否存在
+template<typename T>
+struct has_output_function {
+    template<class U>
+    static auto output(U *ptr)
+    -> decltype(std::declval<std::ostream &>() << *ptr,
+            std::true_type());
+
+    template<class U>
+    static std::false_type output(...);
+
+    static constexpr bool value =
+            decltype(output<T>(nullptr))::value;
+};
+
+template<typename T>
+inline constexpr bool has_output_function_v =
+        has_output_function<T>::value;
+
+
+enum CHARS {
+    ORD,        // 其他类型
+    CHAR,       // char 类型
+    STRING      // string 类型
+};
+
+template<typename T>
+int ischarOrString(T &elem) {
+    using std::decay_t;
+    using std::is_same_v;
+    using element_type = decay_t<decltype(elem)>;
+    constexpr bool is_char_v = is_same_v<element_type, char>;
+    constexpr bool is_string_v = is_same_v<element_type, char *> ||
+                                 is_same_v<element_type, const char *> ||
+                                 is_same_v<element_type, std::string>;
+    if (is_char_v)
+        return CHAR;
+    else if (is_string_v)
+        return STRING;
+    else
+        return ORD;
+}
+
+template<typename T>
+void output(T &elem, int type, std::ostream &os) {
+    switch (type) {
+        case CHAR:
+            os << '\'' << elem << '\'';
+            break;
+        case STRING:
+            os << '\"' << elem << '\"';
+            break;
+        case ORD:
+            os << elem;
+            break;
+    }
+}
+
+template<typename T, typename Cont>
+auto output_element(std::ostream &os, const T &element,
+                    const Cont &)
+-> typename std::enable_if<is_pair<typename Cont::value_type>::value, bool>::type {
+    int ftype = ischarOrString(element.first);
+    int stype = ischarOrString(element.second);
+
+    output(element.first, ftype, os);
+    os << " => ";
+    output(element.second, stype, os);
+    return true;
+}
+
+template<typename T, typename Cont>
+auto output_element(std::ostream &os, const T &element,
+                    const Cont &)
+-> typename std::enable_if<!is_pair<typename Cont::value_type>::value, bool>::type {
+    int etype = ischarOrString(element);
+    output(element, etype, os);
+    return false;
+}
+
+template<typename T, typename U>
+std::ostream &operator<<(std::ostream &os, const std::pair<T, U> &pr) {
+    os << '(' << pr.first << ", " << pr.second << ')';
+    return os;
+}
+
+//template<typename T, typename Cont>
+//auto output_element(std::ostream& os, const T& element,
+//                    const Cont&, const std::true_type)
+//-> decltype(std::declval<typename Cont::key_type>(), os)
+//{
+//    os << element.first << " => " << element.second;
+//    return os;
+//}
+//
+//template <typename T, typename Cont>
+//auto output_element(std::ostream& os, const T& element,
+//                    const Cont&, ...)
+//-> decltype(os)
+//{
+//    os << element;
+//    return os;
+//}
+
+
+
+// 针对没有输出函数的容器处理
+template<typename T,
+        typename = std::enable_if_t<!has_output_function_v<T>>>
+auto operator<<(std::ostream &os, const T &container)
+-> decltype(container.begin(), container.end(), os) {
+    os << "{ ";
+    if (!container.empty()) {
+        bool on_first_element = true;
+        for (auto elem:container) {
+            if (!on_first_element) {
+                os << ", ";
+            } else {
+                on_first_element = false;
+            }
+            output_element(os, elem, container);
+        }
+    }
+    os << " }";
+    return os;
+}
+
+
+#endif //MORDEN_C_OUTPUT_CONTAINER_H