escape code Constants in C++

Question

My instructor gave us some sample code and she used a \a1 \a2 \a3 \a4 \a5 Can someone tell me what it is used for? I can't find it online or in my textbook?

cout<<"\n\t\a\a1----INSERT A NODE IN A BINARY TREE.\a\a";
cout<<"\n\t\a\a2----PRE-ORDER TRAVERSAL.\a\a";
cout<<"\n\t\a\a3----IN-ORDER TRAVERSAL.\a\a";
cout<<"\n\t\a\a4----POST-ORDER TRAVERSAL.\a\a";
cout<<"\n\t\a\a5----EXIT.\a\a";
cout<<"\n\t\a\aENTER CHOICE::\a\a";

http://stackoverflow.com/questions/6727518/cant-get-a-to-output-a-beep-sound — Muthu Ganapathy Nathan, Mar 07 '12 at 12:05
The escape sequence is just `\a`. `\a1` is just bell, then the normal character `1`. So the numbers are not part of the escape sequence. — Magnus Hoff, Mar 07 '12 at 12:08

score 8 · Accepted Answer · edited Apr 23 '13 at 11:57

8

\a is "alert", or "bell". It's listed here, for instance. Running this on a terminal with an actual audible bell (or even a visual one, where the whole screen flashes briefly) would surely be horrible. That's rather strange code to get from an instructor.

The sequence \a1 is simply \a followed by the digit 1, it's not a two-letter escape code.

edited Apr 23 '13 at 11:57

answered Mar 07 '12 at 12:04

unwind

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okay thank you, i am confused and searching in the whole internet and book, i didn't get any answer... but i know \a is a alert beep. – visanio_learner Mar 07 '12 at 12:14
The instructor wanted to really make sure you were paying attention. – Apr 23 '13 at 12:03

score 4 · Answer 2 · answered Mar 07 '12 at 12:04

4

\a is alert, \n is newline, \t is tabulation. 1 is 1 :-)

More here: http://msdn.microsoft.com/en-us/library/h21280bw(v=vs.80).aspx

answered Mar 07 '12 at 12:04

Kos

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score 2 · Answer 3 · answered Mar 07 '12 at 12:04

2

\n - line break
\t - tabulation symbol
\a - sound in the console

So \a1 means \a sound and symbol 1

answered Mar 07 '12 at 12:04

Seagull

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score 1 · Answer 4 · answered Mar 07 '12 at 12:04

1

\a are the speaker bells usually...

answered Mar 07 '12 at 12:04

linello

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escape code Constants in C++

4 Answers4