/r, /n 和 /r/n的來歷與區別

'/r'是回車，'/n'是換行，前者使光標到行首，後者使光標下移一格。通常用的Enter是兩個加起來。下面轉一篇文章。



回車和換行
今天，我總算搞清楚“回車”（carriage return）和“換行”（line feed）這兩個概念的來歷和區別了。
在計算機還沒有出現之前，有一種叫做電傳打字機（Teletype Model 33）的玩意，每秒鐘可以打10個字符。但是它有一個問題，就是打完一行換行的時候，要用去0.2秒，正好可以打兩個字符。要是在這0.2秒裏面，又有新的字符傳過來，那麼這個字符將丟失。

於是，研製人員想了個辦法解決這個問題，就是在每行後面加兩個表示結束的字符。一個叫做“回車”，告訴打字機把打印頭定位在左邊界；另一個叫做“換行”，告訴打字機把紙向下移一行。

這就是“換行”和“回車”的來歷，從它們的英語名字上也可以看出一二。

後來，計算機發明瞭，這兩個概念也就被般到了計算機上。那時，存儲器很貴，一些科學家認爲在每行結尾加兩個字符太浪費了，加一個就可以。於是，就出現了分歧。

Unix系統裏，每行結尾只有“<換行>”，即“/n”；Windows系統裏面，每行結尾是“<換行><回車>”，即“/n/r”；Mac系統裏，每行結尾是“<回車>”。一個直接後果是，Unix/Mac系統下的文件在Windows裏打開的話，所有文字會變成一行；而Windows裏的文件在Unix/Mac下打開的話，在每行的結尾可能會多出一個^M符號。

c語言編程時（windows系統）/r 就是return 回到 本行 行首 這就會把這一行以前的輸出 覆蓋掉
如：
int main() {
cout << "hahaha" << "/r" << "xixi" ;
}
最後只顯示 xixi 而 hahaha 被覆蓋了
/n 是回車＋換行 把光標 先移到 行首 然後換到下一行 也就是 下一行的行首拉
int main() {
cout << "hahaha" << "/n" << "xixi" ;
}
則 顯示
hahaha
xixi

舉例：

SpecFlow中讀取SQL 語句

| SQL script                                                                                                          |
| DECLARE @currentServiceRequestID INT                                                                                |
| SET @currentServiceRequestID = -1                                                                                   |
| WHILE 1=1                                                                                                           |
| BEGIN                                                                                                               |
| DECLARE @tempID INT                                                                                                 |
| SELECT TOP 1 @tempID = ServiceRequestID                                                                             |
| FROM ServiceRequest                                                                                                 |
| WHERE ServiceRequestId > @currentServiceRequestID                                                                   |
| ORDER BY ServiceRequestId                                                                                           |
| IF @@ROWCOUNT = 0 BREAK                                                                                             |
| SELECT @currentServiceRequestID = @tempID                                                                           |
| -- Get uploaded files count                                                                                         |
| DECLARE @uploadedFilesCount INT                                                                                     |
| SELECT @uploadedFilesCount = COUNT(UploadFileId)                                                                    |
| FROM UploadFiles                                                                                                    |
| WHERE ServiceRequestId = @currentServiceRequestID                                                                   |
| AND ISNULL(DeletedBy, '') = ''                                                                                      |
| -- Update allNotes, questionnaire answers, uploaded files count                                                     |
| IF EXISTS (SELECT ServiceRequestID FROM ServiceRequestStatistics WHERE ServiceRequestID = @currentServiceRequestID) |
| BEGIN                                                                                                               |
| UPDATE ServiceRequestStatistics                                                                                     |
| SET UploadFilesCount = @uploadedFilesCount                                                                          |
| ,AllNotes = dbo.GetAllNotesByServiceRequestID(@currentServiceRequestID)                                             |
| ,AllQuestionnaireAnswers = dbo.GetQuestionnaireAnswersByServiceRequestID(@currentServiceRequestID)                  |
| WHERE ServiceRequestID = @currentServiceRequestID                                                                   |
| END                                                                                                                 |
| ELSE BEGIN                                                                                                          |
| INSERT ServiceRequestStatistics(ServiceRequestID, UploadFilesCount, AllNotes, AllQuestionnaireAnswers)              |
| SELECT @currentServiceRequestID                                                                                     |
| ,@uploadedFilesCount                                                                                                |
| ,dbo.GetAllNotesByServiceRequestID(@currentServiceRequestID)                                                        |
| ,dbo.GetQuestionnaireAnswersByServiceRequestID(@currentServiceRequestID)                                            |
| END                                                                                                                 |
| END                                                                                                                 |

-----------code------------

        public void SyncExistingSRInfoToTableServiceRequestStatistics(Table table)
        {
           
            SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["ShotgunDB"].ConnectionString);
           
            connection.Open();
            using (SqlCommand command = new SqlCommand())
            {
                string strScript = "";
                foreach (TableRow eachrow in table.Rows)
                { strScript= strScript + "/r/n" +eachrow[0]; }
               
                command.CommandType = CommandType.Text;
                command.Connection = connection;
                command.CommandText = strScript;
                command.ExecuteNonQuery();
               
            }
        }