Echoing Characters with getchar() in a Loop

[keltix]

If you use getchar() to capture a character and then print it to the stdout in a loop,
why does it first capture the characters in the list (up to whatever max) and then print them all at once?

In other words, how would I echo every character one at a time using a getchar() loop?

 

[keltix]

I want it to print the output like the sample output here:
http://gd.tuwien.ac.at/languages/c/programming-bbrown/c_030.htm

but running that exact same code doesn't work.

 

[rcgldr]

Try _getch() instead.

 

[Coin]

Is _getch() available everywhere?

What is happening to you I think is that you need to flush stdout. In C if you write to a file buffer (stdout is a kind of file buffer) it will buffer a bunch of writes and then write them all at once, for efficiency. "Flushing" forces the write-everything-buffered-at-once operation to happen earlier.

Try putting:
fflush(stdout);
After putch.

 

[keltix]

that just reads without echoing (i.e. w/o printing strokes on screen)

 

[keltix]

Coin, the fflush didn't work.

good guess though

 

[Hurkyl]

On many (most? all?) systems, your program isn't given any of the characters until you press enter. You need to use some system-specific API if you want to trap individual keystrokes.

 

[keltix]

system-specific API?

idk what that is, but yea it only works after pressing enter

 

[Hurkyl]

system-specific API?

Yah. Things like the _getch() function in the Windows API Jeff mentioned. I believe the curses library (*NIX systems) has a similar function.

And, of course, any API that let's you make windows and stuff should have ways to get keypresses.