C question: how do I have a function operate for 10 seconds

[epb613]

I wanna write a function to count how many times I press spacebar in 10 seconds. Is there a timer function or something that I can use? (I'm a C newbie).

I'm guessing it would go along the lines of:

int spaces = 0;
start timer
while (timer < 10) {
check to see if last key pressed was spacebar and if so spaces++
}
printf("%d", spaces);

Sorry for mixing pseudocode and real code.

Thanks in advance.

[epb613]

Hmmm, I actually came up with this based on http://www.cplusplus.com/ref/ctime/:



#include <stdio.h>
#include <time.h>

int main ()
{
long seconds = time(NULL), timeUp = seconds + 10;
printf("\n");
while(seconds < timeUp)
{
/* SPACEBAR COUNTER GOES HERE */
seconds = time(NULL);
}

return 0;
}


The code is pretty simple. The only problem with it is that it doesnt really measure 10 seconds as I lose however far I am into the first second when I start the program. Is there a better way to do this?

Thanks in advance.

[jerome bettis]

#include <stdio.h>
#include <time.h>

int main() {
const int RUNTIME = 10;
time_t start, current;
int spaces = 0;
start = time(NULL);
do {
current = time(NULL);
if (lastKeyPressed == ' ') // you get to figure that out
spaces++;
} while (difftime(current, start) < RUNTIME);
return 0;
}

[epb613]

Oooh that's really cool. My way worked fine but your version is alot cleaner and skips unneccessary steps (using the difftime function). Thanks alot!

[jerome bettis]

lol you're welcome .. it's almost the same thing

not sure how you're gonna do the input part though. i hate I/O in C ... but love it in C++.

[epb613]

:) So lets say I broke down and used c++....

[To build a c++ program, I just type 'g++ program.c' instead of 'cc program.c' - right?]

[epb613]

Haha I found it! After hours of searching... http://cboard.cprogramming.com/showthread.php?t=27714




#include <stdio.h>
#include <termios.h>
#include <unistd.h>

int mygetch( ) {
struct termios oldt,
newt;
int ch;
tcgetattr( STDIN_FILENO, &oldt );
newt = oldt;
newt.c_lflag &= ~( ICANON | ECHO );
tcsetattr( STDIN_FILENO, TCSANOW, &newt );
ch = getchar();
tcsetattr( STDIN_FILENO, TCSANOW, &oldt );
return ch;
}



Using this, my code is:



while(seconds < timeUp)
{
c = mygetch();
printf("%c", c);
if (c == ' ') spaces++;
seconds = time(NULL);
}


I havent incorperated your code in yet. Thanks for all the help by the way!

[LordHunter317]

No, writing C++ isn't as simple as changing your compiler from 'cc' to 'g++'. If that's your current line of thinking, don't even try to write any C++ until you read a complete book on the subject. Thinking in C++ is OK and available online for free.

You don't need that nasty termios using function. You can do what you want using standard C I/O functions.

The fact you didn't realize that tells me you need to go read a good C tutorial as well. K&R's The C Programming Language is the basic tome and an easy enough read.

[epb613]

I don't think it's neccessary to be a C++ expert before having some fun with it. Could you just tell me the code I need?

[jerome bettis]

actually I/O streams in C++ (and C) are pretty complicated. i wouldn't expect everyone to sit here and spoon feed you code all day so you can continue getting drunk and get an A on your assignment.

:-P

www.cplusplus.com read up