Thread: How to build a timer that counts the seconds elapsed?

I'm doing this game for a school, project and one of the extras to have a better grade is a timer. I need to count the time (in seconds) elapsed while i'm running the game until I win it. Meaning, I start the game, the timer starts counting the seconds, I win the game, the timer stops and I need to return the number of seconds elapsed.

One way to do this would be: get the system time at start and at the end, then calculate the seconds. However, I would like to have the timer on screen, chaging within each second. Is it possible without much code? How?

I'll hear any other suggestion too...

I forgot to tell I'm on linux...

But I don't see how can I update the timer every second if my game has user input... I'm using ncurses by the way. And I'm using the getch() function to read input. When the code reaches a line with getch(), it won't continue without pressing any key, so, how can I update a timer every second with that restriction?

As you're beginning to see, it's a PITA when the timer is put with a program that does a lot of other things.

But Wait! There's more! (says the Ronco wizard, Ron Popeil), because the timer won't look right UNLESS you check it about 3 or 4 times per second. Basically because the OS is busy doing other things - but it looks jerky and you can miss seconds if you don't check it at least 3 times per second.

Every function and every loop in every function, that takes more than 1/3rd of a second, will need to have a little bit of timer code in them, to keep the clock right. Time is relentless and a 1/3rd of a second is not very long!

But it's doable.

IMO the start time & end time variables should be a global variables, because nearly every function will need access to them.

The easiest way (assuming you are on Win32) -

Code:

char szString[64];
DWORD dwStartTime;
DWORD dwElapseTime;
RECT Rect; // rectangle of the client area
HDC hdc; // DC of the client area

dwStartTime = GetTickCount();
while(TRUE){

     /* game code goes here */

     dwElapsedTime = (GetTickCount() - dwStartTime) / 1000;
     sprintf((char*)&szString[0] , "Time : %d\0" , dwElapsedTime);
     DrawText(hdc , (char*)&szString[0] , -1 , &Rect , DT_TOP | DT_CENTER );

     }

Hey guys: OP writes: "forgot to tell I'm on linux..."

Window's code is irrelevant, in this case.

I'm still confused and I don't understand how would I implement this on my code... For instance, I don't use the getch() directly, I have a custom function to read input with getch() to fit my needs. On another piece of code, I have while loop that will read the directional keys (to move the cursor in a matrix).

The function I'm using is this:

Code:

void getInput(int l, int c, string str, int limit, bool pwd) {
	int i = 0;
	int ch = 0;
	
	// Activates the cursor and changes the input color
	
	curs_set(1);
	attron(COLOR_PAIR(6));
	
	// Loops until the user presses the Return key
	
	while(ch != '\n') {
		ch = mvgetch(l, c);

		if(ch != '\n' && ch != '\t') {
			// Did the user pressed the backspace key?
			
			if(i > 0 && (ch == KEY_BACKSPACE || ch == 127)) {
				move(l, --c);
				
				attroff(COLOR_PAIR(6));
				mvprintw(l, c, " ");
				attron(COLOR_PAIR(6));
				
				refresh();
					
				i--;
			} else {
				// Is the char invalid or the user went over the limit?
				
				if(i < limit && (isalnum(ch) || isspace(ch))) {
					str[i++] = (char)ch;
					
					// Hide input? (password)
					
					if(pwd) mvprintw(l, c++, "*");
					else mvprintw(l, c++, "%c", ch);
					
					refresh();
				}
			}
		}
	}
	
	// Deactivates the cursor and removes the input color
	
	curs_set(0);
	attroff(COLOR_PAIR(6));
	
	// Terminates the string and/or removes the line termination
	
	if(str[i-1] == '\n') {
		str[i-1] = '\0';
	} else {
		str[i] = '\0';
	}
}

And I use it like this:

Code:

char buffer[10];

getInput(0, 0, buffer, sizeof(buffer)-1, FALSE);

Could you provide me with the simplest and full example of how you would put a timer on screen updating everysecond and using getInput() to read user input? For instance, inside this loop:

Code:

do {
	getInput(0, 0, buffer, sizeof(buffer)-1, FALSE);
} while(buffer[0] != 'q');

But I don't get how that would work... The show_timer() function is called and the timer will be shown, let's say 5seconds. In the next line the function mvgetch() will be called, which is waiting for user input, if I only press a key after 5 seconds, the timer will go from 5seconds to 10seconds, and what I want is the timer to be updated every second while i'm waiting for user input, that's my problem.

If I'm waiting for user input, the code is "halted" in the getch() call, how can I update the timer if the code does not move from that line until I press a key? That's what I don't get and I don't see how all of your help would solve that... Maybe I'm too dumb, but I can't see it.