How do I do autofill a text when Tab key is pressed after a period from STDIN using C?
Input would look like,
C:\>autofil.exe Hello
C:\>autofil.exe Hello. ( When I enter a period, it should autofil Hello after the period)
C:\>autofil.exe Hello.World *World is autofilled when period was entered.
Second requirement is if I am at
C:\>autofil.exe Hello.World (And when i press Tab key, `World` should print with other suggestions, as `Friend`, and if I press Tab again, print `Matt`, and scroll so on when tab is pressed... )
Well, that is my requirement. Tab complete to autofill text. Also, want to know how to read the Tab key from STDIN.
Thanks!
You could use Readline GNU library For Windows, is pretty easy to use, the other way around is to use PDcurses/Ncurses (are almost the same) and do it by hand (handling console behavior and such).
In case you use readline, to acomplish autocomplete is as simple as doing:
rl_bind_key('\t', rl_complete);
char *input = readline("C:\>");
In case you use Ncurses/PDcurses, you will have to do a little more work :)
First you save actual console parameters.
Then you set echo of the input off with noecho().
You will have to handle input and parse the arguments to call programs.
Also you will have to search in dirs (current and the ones on PATH variable) for things matching your current input.
Before ending your program set again the saved console parameters.
Ncurses How-To Is an easy right to the point guide.
Posix curses definition Contains functions and key definitions.
Related
I am trying to code a little console chat-program in C on linux.
So far I coded it in a way that both chatting partners are only able to alternately send/recv, because these function calls are blocking by default.
Now I would like to modify that program, so that both are able to send and receive simultaneously.
The problem that I find is, that once you typed some input to the terminal, I don't know how to output received messages, without messing up the current input line of the terminal.
If there was a way to delete that current input line, you could temporarily save that line, print the new message and put the input line right back.
However, I was not able to find a solution for this problem on the internet.
Is it possible to delete the current input line, and if not, how else could I achieve what I want?
I think you should look into ncurses as Edd said in his comment.
It would allow you to easily manage contents in your terminal window, which sounds like a good idea for your chat program.
All you'd need to do is store your messages in 2 character arrays:
char incoming[MSG_MAX]
and
char outgoing[MSG_MAX]
Then you can output those messages wherever you want in your terminal window, since ncurses allows you to specify x,y coordinates on where to put your text.
Then a simple wrapper for one of ncurses erase() family functions would allow you to delete characters from specify x,y coordinates in your terminal window.
Edit: MSG_MAX is not an actual ncurses macro.
I'm writing a C program that requires to hide the characters a user types from the screen during the program execution. For example, when running the following loop
while (1)
{
//do some work
}
the console displays the blinking cursor (that's good). BUT, when the user types keys on the keyboard, these keys are being echoed out to the console. To visualize it better:
Step 1: Starting the program
root#debian:/home/root# ./program
_
Step 2: User types some characters (even though he shouldn't)
root#debian:/home/root# ./program
AdajfsaSJ_
The characters get echoed on the console. How can I stop this? I know it's theoretically possible, but I can't find out how to implement it.
If you need a better example for what I want to achieve, use the screen command on an empty serial port. screen /dev/tty30 for example. This empties the console and runs the program, HOWEVER, the user is not able to enter any characters (there's a blinking white cursor block and no keyboard characters are being echoed to the console). That's what I need.
Any insight would help, thanks!
Use termios() to turn off the ECHO flag of the terminal.
To turn off the text cursor, use the termcap library to control the cursor visibility.
I'm writing a program that needs to ask the user a yes or no question at the end. Going based off the example .exe my teacher provided us, the line is supposed to print out "Would you like to print an Amortization Table(Y/N)?Y" and it looks for one keystroke from the user. The Y is printed out following the question like I typed, as it is supposed to represent the default choice so if the user presses [y], [shift + y], or [enter] it goes to the function that does the amortization table and if the user presses anything else it goes to the next line When it gets the input from the user it processes the keystroke instantly as it is pressed (it does not need [enter] to process the input) without letting the keystroke appear on the command prompt. I have tried all the functions I can think of to do this (getc, getchar, getche) but everything I have tried ends up printing the user's input. Does anyone know what function he used or what trick he is doing to keep the keystroke from appearing in the command prompt? Thanks for your help in advance, I am obviously new to programming.
For the Windows platform, use the _getch() function from <conio.h> to read a keypress without buffering or echo.
Read the function description on MSDN
I have a C code, which prompts users for list of directory name, it just uses plain scanf() to receive the input and proceeds. Now I would like to provide autocomplete for directory names (like bash does). Say user enter /home/a and press TAB - it displays list of available user directories that begins with 'a'.how to achieve this?
scanf is not suitable for any kind of auto-complete or even interactive editing beyond the basic level (essentially just backspace) that the kernel cooked-mode terminal driver provides. If you want to do fancier interactive input, you need to change the terminal modes so you get each key event and process them yourself, or you can use a library like readline that does this for you.
I have this program in C that reads the input like this:
cod1 = getch ();
if (kbhit())
cod2 = getch ();
I can read every Ctrl+Char possible sequences, except for Ctrl+C, that closes the program - that is OK, and Ctrl+S, that simple is not catch. But I wanted to make Ctrl+S to be the save function in my program; how could I do that? Furthermore, is it possible to read Alt+Char characters? Because it reads it as a regular character, e.g., Alt+A is read with the same codes as A.
Your problem is that input probably gets eaten by terminal emulator.
For example Alt+<Whatever> is often reserved for menu shortcuts (e.g. Alt+F opens File menu). Matching characters are often hilighted once you hold Alt (F get's underscored in File).
Ctrl+S is reserved for Stops all output on screen (XOFF) (again your terminal emulator does that).
As for using Alt+<...> as shortcuts in your command line application. As far as I'm concerned holding Alt doesn't affect character received, it just sets flags which are hard to access in console. Even in GUI application (in Windows) it's quite tricky and you have to use function like GetAsyncState() to check whether alt was pressed.