book: add line breaks for code formatting (changkun#226)

Author: lucoiso

book/en-us/05-pointers.md

@@ -58,20 +58,26 @@ 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
+
 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 has reset
+std::cout << "pointer2.use_count() = " 
+    << pointer2.use_count() << std::endl; // 0, pointer2 has reset        
 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 << "pointer2.use_count() = " << pointer2.use_count() << std::endl; // 0
-std::cout << "pointer3.use_count() = " << pointer3.use_count() << std::endl; // 0, pointer3 has reset
+std::cout << "pointer3.use_count() = " 
+    << pointer3.use_count() << std::endl; // 0, pointer3 has reset
 ```
 
 ## 5.3 `std::unique_ptr`

book/en-us/06-regex.md

@@ -84,7 +84,8 @@ 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;
@@ -186,29 +187,32 @@ 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
+    // 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/
     // 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--;
-        }
+    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--;
+            }
 
         // (...)
     };