book: formatting style updates (changkun#231)

book/en-us/02-usability.md

@@ -214,7 +214,8 @@ int main() {
     }
 
     // should output: 1, 4, 3, 4. can be simplified using `auto`
-    for (std::vector<int>::iterator element = vec.begin(); element != vec.end(); ++element)
+    for (std::vector<int>::iterator element = vec.begin(); element != vec.end(); 
+        ++element)
         std::cout << *element << std::endl;
 }
 ```
@@ -301,7 +302,8 @@ int main() {
     MagicFoo magicFoo = {1, 2, 3, 4, 5};
 
     std::cout << "magicFoo: ";
-    for (std::vector<int>::iterator it = magicFoo.vec.begin(); it != magicFoo.vec.end(); ++it) 
+    for (std::vector<int>::iterator it = magicFoo.vec.begin(); 
+        it != magicFoo.vec.end(); ++it) 
         std::cout << *it << std::endl;
 }
 ```

book/en-us/03-runtime.md

@@ -221,8 +221,8 @@ int foo(int a, int b, int c) {
     ;
 }
 int main() {
-    // bind parameter 1, 2 on function foo, and use std::placeholders::_1 as placeholder
-    // for the first parameter.
+    // bind parameter 1, 2 on function foo, 
+    // and use std::placeholders::_1 as placeholder for the first parameter.
     auto bindFoo = std::bind(foo, std::placeholders::_1, 1,2);
     // when call bindFoo, we only need one param left
     bindFoo(1);
@@ -355,7 +355,8 @@ int main()
     std::string&& rv1 = std::move(lv1); // legal, std::move can convert lvalue to rvalue
     std::cout << rv1 << std::endl;      // string,
 
-    const std::string& lv2 = lv1 + lv1; // legal, const lvalue reference can extend temp variable's lifecycle
+    const std::string& lv2 = lv1 + lv1; // legal, const lvalue reference can
+                                        // extend temp variable's lifecycle
     // lv2 += "Test";                   // illegal, const ref can't be modified
     std::cout << lv2 << std::endl;      // string,string,
 
@@ -482,8 +483,9 @@ int main() {
     // "str: Hello world."
     std::cout << "str: " << str << std::endl;
 
-    // use push_back(const T&&), no copy
-    // the string will be moved to vector, and therefore std::move can reduce copy cost
+    // use push_back(const T&&), 
+    // no copy the string will be moved to vector, 
+    // and therefore std::move can reduce copy cost
     v.push_back(std::move(str));
     // str is empty now
     std::cout << "str: " << str << std::endl;

book/en-us/05-pointers.md

@@ -57,35 +57,35 @@ And see the reference count of an object by `use_count()`. E.g:
 auto pointer = std::make_shared<int>(10);
 auto pointer2 = pointer; // reference count+1
 auto pointer3 = pointer; // reference count+1
-int *p = pointer.get(); // no increase of reference count
+int *p = pointer.get();  // no increase of reference count
 
-std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl; // 3
+std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl;   // 3
 std::cout << "pointer2.use_count() = " << pointer2.use_count() << std::endl; // 3
 std::cout << "pointer3.use_count() = " << pointer3.use_count() << std::endl; // 3
 
 pointer2.reset();
 std::cout << "reset pointer2:" << std::endl;
 
-std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl; // 2
+std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl;   // 2
 std::cout << "pointer2.use_count() = " 
-    << pointer2.use_count() << std::endl; // 0, pointer2 has reset        
+    << pointer2.use_count() << std::endl;                // pointer2 has reset, 0
 std::cout << "pointer3.use_count() = " << pointer3.use_count() << std::endl; // 2
 
 pointer3.reset();
 std::cout << "reset pointer3:" << std::endl;
 
-std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl; // 1
+std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl;   // 1
 std::cout << "pointer2.use_count() = " << pointer2.use_count() << std::endl; // 0
 std::cout << "pointer3.use_count() = " 
-    << pointer3.use_count() << std::endl; // 0, pointer3 has reset
+    << pointer3.use_count() << std::endl;                // pointer3 has reset, 0
 ```
 
 ## 5.3 `std::unique_ptr`
 
 `std::unique_ptr` is an exclusive smart pointer that prohibits other smart pointers from sharing the same object, thus keeping the code safe:
 
 ```cpp
-std::unique_ptr<int> pointer = std::make_unique<int>(10); // make_unique was introduced in C++14
+std::unique_ptr<int> pointer = std::make_unique<int>(10); // make_unique, from C++14
 std::unique_ptr<int> pointer2 = pointer; // illegal
 ```
 

book/en-us/06-regex.md

@@ -84,8 +84,9 @@ We use a simple example to briefly introduce the use of this library. Consider t
 
 int main() {
     std::string fnames[] = {"foo.txt", "bar.txt", "test", "a0.txt", "AAA.txt"};
-    // In C++, `\` will be used as an escape character in the string. In order for `\.`
-    // to be passed as a regular expression, it is necessary to perform second escaping of `\`, thus we have `\\.`
+    // In C++, `\` will be used as an escape character in the string.
+    // In order for `\.` to be passed as a regular expression,
+    // it is necessary to perform second escaping of `\`, thus we have `\\.`
     std::regex txt_regex("[a-z]+\\.txt");
     for (const auto &fname: fnames)
         std::cout << fname << ": " << std::regex_match(fname, txt_regex) << std::endl;
@@ -104,7 +105,8 @@ std::smatch base_match;
 for(const auto &fname: fnames) {
     if (std::regex_match(fname, base_match, base_regex)) {
         // the first element of std::smatch matches the entire string
-        // the second element of std::smatch matches the first expression with brackets
+        // the second element of std::smatch matches the first expression
+        // with brackets
         if (base_match.size() == 2) {
             std::string base = base_match[1].str();
             std::cout << "sub-match[0]: " << base_match[0].str() << std::endl;
@@ -187,32 +189,36 @@ Please implement the member functions `start()` and `parse_request`. Enable serv
 template<typename SERVER_TYPE>
 void start_server(SERVER_TYPE &server) {
 
-    // process GET request for /match/[digit+numbers], e.g.
-    // GET request is /match/abc123, will return abc123
-    server.resource["fill_your_reg_ex"]["GET"] = [](ostream& response, Request& request) {
+    // process GET request for /match/[digit+numbers],
+    // e.g. GET request is /match/abc123, will return abc123
+    server.resource["fill_your_reg_ex"]["GET"] =
+        [](ostream& response, Request& request)
+    {
         string number=request.path_match[1];
         response << "HTTP/1.1 200 OK\r\nContent-Length: " << number.length()
             << "\r\n\r\n" << number;
     };
 
-    // peocess default GET request; anonymous function will be called if no other matches
-    // response files in folder web/
+    // peocess default GET request;
+    // anonymous function will be called
+    // if no other matches response files in folder web/
     // default: index.html
     server.default_resource["fill_your_reg_ex"]["GET"] =
-        [](ostream& response, Request& request) {
-            string filename = "www/";
-
-            string path = request.path_match[1];
-
-            // forbidden use `..` access content outside folder web/
-            size_t last_pos = path.rfind(".");
-            size_t current_pos = 0;
-            size_t pos;
-            while((pos=path.find('.', current_pos)) != string::npos && pos != last_pos) {
-                current_pos = pos;
-                path.erase(pos, 1);
-                last_pos--;
-            }
+        [](ostream& response, Request& request)
+    {
+        string filename = "www/";
+
+        string path = request.path_match[1];
+
+        // forbidden use `..` access content outside folder web/
+        size_t last_pos = path.rfind(".");
+        size_t current_pos = 0;
+        size_t pos;
+        while((pos=path.find('.', current_pos)) != string::npos && pos != last_pos) {
+            current_pos = pos;
+            path.erase(pos, 1);
+            last_pos--;
+        }
 
         // (...)
     };

book/en-us/07-thread.md

@@ -145,7 +145,8 @@ int main() {
     std::cout << "waiting...";
     result.wait(); // block until future has arrived
     // output result
-    std::cout << "done!" << std:: endl << "future result is " << result.get() << std::endl;
+    std::cout << "done!" << std:: endl << "future result is " 
+              << result.get() << std::endl;
     return 0;
 }
 ```
@@ -196,7 +197,8 @@ int main() {
             // temporal unlock to allow producer produces more rather than
             // let consumer hold the lock until its consumed.
             lock.unlock();
-            std::this_thread::sleep_for(std::chrono::milliseconds(1000)); // consumer is slower
+            // consumer is slower
+            std::this_thread::sleep_for(std::chrono::milliseconds(1000));
             lock.lock();
             if (!produced_nums.empty()) {
                 std::cout << "consuming " << produced_nums.front() << std::endl;
@@ -272,7 +274,7 @@ This is a very strong set of synchronization conditions, in other words when it
 This seems too harsh for a variable that requires only atomic operations (no intermediate state).
 
 The research on synchronization conditions has a very long history, and we will not go into details here. Readers should understand that under the modern CPU architecture, atomic operations at the CPU instruction level are provided.
-Therefore, in the C++11 multi-threaded shared variable reading and writing, the introduction of the `std::atomic` template, so that we instantiate an atomic type, will be a
+Therefore, in the C++11 multi-threaded shared variable reading and writing, the introduction of the `std::atomic` template, so that we instantiate an atomic type, will be an
 Atomic type read and write operations are minimized from a set of instructions to a single CPU instruction. E.g:
 
 ```cpp
@@ -417,8 +419,11 @@ Weakening the synchronization conditions between processes, usually we will cons
    ```
    3 4 4 4 // The write operation of x was quickly observed
    0 3 3 4 // There is a delay in the observed time of the x write operation
-   0 0 0 4 // The last read read the final value of x, but the previous changes were not observed.
-   0 0 0 0 // The write operation of x is not observed in the current time period, but the situation that x is 4 can be observed at some point in the future.
+   0 0 0 4 // The last read read the final value of x, 
+           // but the previous changes were not observed.
+   0 0 0 0 // The write operation of x is not observed in the current time period, 
+           // but the situation that x is 4 can be observed 
+           // at some point in the future.
    ```
 
 ### Memory Orders
@@ -480,9 +485,8 @@ To achieve the ultimate performance and achieve consistency of various strength
    });
    std::thread acqrel([&]() {
        int expected = 1; // must before compare_exchange_strong
-       while(!flag.compare_exchange_strong(expected, 2, std::memory_order_acq_rel)) {
+       while(!flag.compare_exchange_strong(expected, 2, std::memory_order_acq_rel)) 
            expected = 1; // must after compare_exchange_strong
-       }
        // flag has changed to 2
    });
    std::thread acquire([&]() {

book/zh-cn/02-usability.md

@@ -176,7 +176,8 @@ int main() {
     }
 
     // 将输出 1, 4, 3, 4
-    for (std::vector<int>::iterator element = vec.begin(); element != vec.end(); ++element)
+    for (std::vector<int>::iterator element = vec.begin(); element != vec.end(); 
+        ++element)
         std::cout << *element << std::endl;
 }
 ```
@@ -228,7 +229,7 @@ int main() {
 }
 ```
 
-为了解决这个问题，C++11 首先把初始化列表的概念绑定到了类型上，并将其称之为 `std::initializer_list`，允许构造函数或其他函数像参数一样使用初始化列表，这就为类对象的初始化与普通数组和 POD 的初始化方法提供了统一的桥梁，例如：
+为解决这个问题，C++11 首先把初始化列表的概念绑定到类型上，称其为 `std::initializer_list`，允许构造函数或其他函数像参数一样使用初始化列表，这就为类对象的初始化与普通数组和 POD 的初始化方法提供了统一的桥梁，例如：
 
 ```cpp
 #include <initializer_list>
@@ -249,7 +250,9 @@ int main() {
     MagicFoo magicFoo = {1, 2, 3, 4, 5};
 
     std::cout << "magicFoo: ";
-    for (std::vector<int>::iterator it = magicFoo.vec.begin(); it != magicFoo.vec.end(); ++it) std::cout << *it << std::endl;
+    for (std::vector<int>::iterator it = magicFoo.vec.begin(); 
+        it != magicFoo.vec.end(); ++it) 
+        std::cout << *it << std::endl;
 }
 ```
 

book/zh-cn/03-runtime.md

@@ -136,7 +136,7 @@ Lambda 表达式的本质是一个和函数对象类型相似的类类型（称
 #include <iostream>
 
 using foo = void(int); // 定义函数类型, using 的使用见上一节中的别名语法
-void functional(foo f) { // 定义在参数列表中的函数类型 foo 被视为退化后的函数指针类型 foo*
+void functional(foo f) { // 参数列表中定义的函数类型 foo 被视为退化后的函数指针类型 foo*
     f(1); // 通过函数指针调用函数
 }
 
@@ -193,7 +193,8 @@ int foo(int a, int b, int c) {
     ;
 }
 int main() {
-    // 将参数1,2绑定到函数 foo 上，但是使用 std::placeholders::_1 来对第一个参数进行占位
+    // 将参数1,2绑定到函数 foo 上，
+    // 但使用 std::placeholders::_1 来对第一个参数进行占位
     auto bindFoo = std::bind(foo, std::placeholders::_1, 1,2);
     // 这时调用 bindFoo 时，只需要提供第一个参数即可
     bindFoo(1);
@@ -551,7 +552,7 @@ constexpr _Tp&& forward(typename std::remove_reference<_Tp>::type&& __t) noexcep
 ```
 
 在这份实现中，`std::remove_reference` 的功能是消除类型中的引用，
-而 `std::is_lvalue_reference` 用于检查类型推导是否正确，在 `std::forward` 的第二个实现中
+`std::is_lvalue_reference` 则用于检查类型推导是否正确，在 `std::forward` 的第二个实现中
 检查了接收到的值确实是一个左值，进而体现了坍缩规则。
 
 当 `std::forward` 接受左值时，`_Tp` 被推导为左值，所以返回值为左值；而当其接受右值时，

book/zh-cn/05-pointers.md

@@ -19,15 +19,15 @@ order: 5
 也就是我们常说的 RAII 资源获取即初始化技术。
 
 凡事都有例外，我们总会有需要将对象在自由存储上分配的需求，在传统 C++ 里我们只好使用 `new` 和 `delete` 去
-『记得』对资源进行释放。而 C++11 引入智能指针的概念，使用引用计数的想法，让程序员不再需要关心手动释放内存。
-这些智能指针就包括 `std::shared_ptr`/`std::unique_ptr`/`std::weak_ptr`，使用它们需要包含头文件 `<memory>`。
+『记得』对资源进行释放。而 C++11 引入了智能指针的概念，使用了引用计数的想法，让程序员不再需要关心手动释放内存。
+这些智能指针包括 `std::shared_ptr`/`std::unique_ptr`/`std::weak_ptr`，使用它们需要包含头文件 `<memory>`。
 
 > 注意：引用计数不是垃圾回收，引用计数能够尽快收回不再被使用的对象，同时在回收的过程中也不会造成长时间的等待，
 > 更能够清晰明确的表明资源的生命周期。
 
 ## 5.2 `std::shared_ptr`
 
-`std::shared_ptr` 是一种智能指针，它能够记录多少个 `shared_ptr` 共同指向一个对象，从而消除显式的调用 
+`std::shared_ptr` 是一种智能指针，它能够记录多少个 `shared_ptr` 共同指向一个对象，从而消除显式的调用
 `delete`，当引用计数变为零的时候就会将对象自动删除。
 
 但还不够，因为使用 `std::shared_ptr` 仍然需要使用 `new` 来调用，这使得代码出现了某种程度上的不对称。
@@ -59,21 +59,23 @@ int main() {
 auto pointer = std::make_shared<int>(10);
 auto pointer2 = pointer; // 引用计数+1
 auto pointer3 = pointer; // 引用计数+1
-int *p = pointer.get(); // 这样不会增加引用计数
-std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl; // 3
+int *p = pointer.get();  // 这样不会增加引用计数
+std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl;   // 3
 std::cout << "pointer2.use_count() = " << pointer2.use_count() << std::endl; // 3
 std::cout << "pointer3.use_count() = " << pointer3.use_count() << std::endl; // 3
 
 pointer2.reset();
 std::cout << "reset pointer2:" << std::endl;
-std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl; // 2
-std::cout << "pointer2.use_count() = " << pointer2.use_count() << std::endl; // 0, pointer2 已 reset
+std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl;   // 2
+std::cout << "pointer2.use_count() = "
+          << pointer2.use_count() << std::endl;           // pointer2 已 reset; 0
 std::cout << "pointer3.use_count() = " << pointer3.use_count() << std::endl; // 2
 pointer3.reset();
 std::cout << "reset pointer3:" << std::endl;
-std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl; // 1
+std::cout << "pointer.use_count() = " << pointer.use_count() << std::endl;   // 1
 std::cout << "pointer2.use_count() = " << pointer2.use_count() << std::endl; // 0
-std::cout << "pointer3.use_count() = " << pointer3.use_count() << std::endl; // 0, pointer3 已 reset
+std::cout << "pointer3.use_count() = "
+          << pointer3.use_count() << std::endl;           // pointer3 已 reset; 0
 ```
 
 ## 5.3 `std::unique_ptr`

book/zh-cn/06-regex.md

@@ -94,7 +94,8 @@ C++11 提供的正则表达式库操作 `std::string` 对象，
 
 int main() {
     std::string fnames[] = {"foo.txt", "bar.txt", "test", "a0.txt", "AAA.txt"};
-    // 在 C++ 中 \ 会被作为字符串内的转义符，为使 \. 作为正则表达式传递进去生效，需要对 \ 进行二次转义，从而有 \\.
+    // 在 C++ 中 \ 会被作为字符串内的转义符，
+    // 为使 \. 作为正则表达式传递进去生效，需要对 \ 进行二次转义，从而有 \\.
     std::regex txt_regex("[a-z]+\\.txt");
     for (const auto &fname: fnames)
         std::cout << fname << ": " << std::regex_match(fname, txt_regex) << std::endl;
@@ -103,7 +104,7 @@ int main() {
 
 另一种常用的形式就是依次传入 `std::string`/`std::smatch`/`std::regex` 三个参数，
 其中 `std::smatch` 的本质其实是 `std::match_results`。
-在标准库中， `std::smatch` 被定义为了 `std::match_results<std::string::const_iterator>`，
+故而在标准库的实现中， `std::smatch` 被定义为了 `std::match_results<std::string::const_iterator>`，
 也就是一个子串迭代器类型的 `match_results`。
 使用 `std::smatch` 可以方便的对匹配的结果进行获取，例如：
 
@@ -193,16 +194,23 @@ protected:
 template<typename SERVER_TYPE>
 void start_server(SERVER_TYPE &server) {
 
-    // process GET request for /match/[digit+numbers], e.g. GET request is /match/abc123, will return abc123
-    server.resource["fill_your_reg_ex"]["GET"] = [](ostream& response, Request& request) {
+    // process GET request for /match/[digit+numbers], 
+    // e.g. GET request is /match/abc123, will return abc123
+    server.resource["fill_your_reg_ex"]["GET"] = 
+        [](ostream& response, Request& request) 
+    {
         string number=request.path_match[1];
-        response << "HTTP/1.1 200 OK\r\nContent-Length: " << number.length() << "\r\n\r\n" << number;
+        response << "HTTP/1.1 200 OK\r\nContent-Length: " 
+                 << number.length() << "\r\n\r\n" << number;
     };
 
-    // peocess default GET request; anonymous function will be called if no other matches
-    // response files in folder web/
+    // peocess default GET request; 
+    // anonymous function will be called 
+    // if no other matches response files in folder web/
     // default: index.html
-    server.default_resource["fill_your_reg_ex"]["GET"] = [](ostream& response, Request& request) {
+    server.default_resource["fill_your_reg_ex"]["GET"] = 
+        [](ostream& response, Request& request) 
+    {
         string filename = "www/";
 
         string path = request.path_match[1];