What are carriage return, linefeed, and form feed?

Question

What is the meaning of the following control characters:

1. Carriage return

2. Line feed

3. Form feed

Answer 1

\f is used for page break. You cannot see any effect in the console. But when you use this character constant in your file then you can see the difference.

Other example is that if you can redirect your output to a file then you don't have to write a file or use file handling.

For ex:

Write this code in c++

void main()    
{
    clrscr();
    cout<<"helloooooo" ;

    cout<<"\f";
    cout<<"hiiiii" ;

}

and when you compile this it generate an exe(for ex. abc.exe)

then you can redirect your output to a file using this:

abc > xyz.doc

then open the file xyz.doc you can see the actual page break between hellooo and hiiii....

Answer 2

"\n" is the linefeed character. It means end the present line and go to a new line for anyone who is reading it.

Answer 3

Have a look at Wikipedia:

Systems based on ASCII or a compatible character set use either LF (Line feed, '\n', 0x0A, 10 in decimal) or CR (Carriage return, '\r', 0x0D, 13 in decimal) individually, or CR followed by LF (CR+LF, 0x0D 0x0A). These characters are based on printer commands: The line feed indicated that one line of paper should feed out of the printer, and a carriage return indicated that the printer carriage should return to the beginning of the current line.

Answer 4

On old paper-printer terminals, advancing to the next line involved two actions: moving the print head back to the beginning of the horizontal scan range (carriage return) and advancing the roll of paper being printed on (line feed).

Since we no longer use paper-printer terminals, those actions aren't really relevant anymore, but the characters used to signal them have stuck around in various incarnations.

Answer 5

Carriage return means to return to the beginning of the current line without advancing downward. The name comes from a printer's carriage, as monitors were rare when the name was coined. This is commonly escaped as "\r", abbreviated CR, and has ASCII value 13 or 0x0D.

Linefeed means to advance downward to the next line; however, it has been repurposed and renamed. Used as "newline", it terminates lines (commonly confused with separating lines). This is commonly escaped as "\n", abbreviated LF or NL, and has ASCII value 10 or 0x0A. CRLF (but not CRNL) is used for the pair "\r\n".

Form feed means advance downward to the next "page". It was commonly used as page separators, but now is also used as section separators. (It's uncommonly used in source code to divide logically independent functions or groups of functions.) Text editors can use this character when you "insert a page break". This is commonly escaped as "\f", abbreviated FF, and has ASCII value 12 or 0x0C.

As control characters, they may be interpreted in various ways.

The most common difference (and probably the only one worth worrying about) is lines end with CRLF on Windows, NL on Unix-likes, and CR on older Macs (the situation has changed with OS X to be like Unix). Note the shift in meaning from LF to NL, for the exact same character, gives the differences between Windows and Unix. (Windows is, of course, newer than Unix, so it didn't adopt this semantic shift. I don't know the history of Macs using CR.) Many text editors can read files in any of these three formats and convert between them, but not all utilities can.

Form feed is a bit more interesting (even though less commonly used directly), and with the usual definition of page separator, it can only come between lines (e.g. after the newline sequence of NL, CRLF, or CR) or at the start or end of the file.