I've been confused by the difference between \r and \n for a long time. Now I found a really wonderful answer from Stackoverflow!
In terms of ascii code, it's 3 -- since they're 10 and 13 respectively;-).
But seriously, there are many:
- in Unix and all Unix-like systems,
\nis the code for end-of-line,\rmeans nothing special - as a consequence, in C and most languages that somehow copy it (even remotely),
\nis the standard escape sequence for end of line (translated to/from OS-specific sequences as needed) - in old Mac systems (pre-OS X),
\rwas the code for end-of-line instead - in Windows (and many old OSs), the code for end of line is 2 characters, `\r\n', in this order
- as a (surprising;-) consequence (harking back to OSs much older than Windows),
\r\nis the standard line-termination for text formats on the Internet - for electromechanical teletype-like "terminals",
\rcommands the carriage to go back leftwards until it hits the leftmost stop (a slow operation),\ncommands the roller to roll up one line (a much faster operation) -- that's the reason you always have\rbefore\n, so that the roller can move while the carriage is still going leftwards!-) - for character-mode terminals (typically emulating even-older printing ones as above), in raw mode,
\rand\nact similarly (except both in terms of the cursor, as there is no carriage or roller;-)
In practice, in the modern context of writing to a text file, you should always use
PS: when I coded in Xinu, things work like this.
/***Without '\r'*****************/
for (int i = 0; i < 3; i++)
kprintf ("Hello World\n");
/*******************************/
Then the output is:
Hello World
Hello World
Hello World
/*******With '\r'******************/
for (int i = 0; i < 3; i++)
kprintf ("Hello World\r\n");
/*********************************/
Output is:
Hello World
Hello World
Hello World
So I guess we can understand like this. '\n' moves the cursor to the next line. '\r' moves cursor to the leftmost of the current line.
\n(the underlying runtime will translate that if you're on a weird OS, e.g., Windows;-). The only reason to use \r is if you're writing to a character terminal (or more likely a "console window" emulating it) and want the next line you write to overwrite the last one you just wrote (sometimes used for goofy "ascii animation" effects of e.g. progress bars) -- this is getting pretty obsolete in a world of GUIs, though;-).PS: when I coded in Xinu, things work like this.
/***Without '\r'*****************/
for (int i = 0; i < 3; i++)
kprintf ("Hello World\n");
/*******************************/
Then the output is:
Hello World
Hello World
Hello World
/*******With '\r'******************/
for (int i = 0; i < 3; i++)
kprintf ("Hello World\r\n");
/*********************************/
Output is:
Hello World
Hello World
Hello World
So I guess we can understand like this. '\n' moves the cursor to the next line. '\r' moves cursor to the leftmost of the current line.
