constant updating

[Wick]

I'm writing a program to display the time of day. Although basic functionality is already done, I'd like the clock to keep updating until a user keystroke. That's why I put in the indefinite while loop.

Here's the source (though it may only work with windows):

#include <iostream>
#include <stdlib.h>
#include <time.h>

using namespace std;

int main()
{
      while(true)
      {
          time_t now;
          time(&now);
          cout<<now<<" = ";
          unsigned int clock = now - 18000; //18000 could be any midnight
          unsigned int hour = (clock / 3600) % 24;
          unsigned int minute = (clock % 3600) / 60;
          unsigned int second = clock % 60;
          cout<<hour % 12<<":";
          if(minute < 10)
          {
              cout<<"0";
          }
          cout<<minute<<":";
          if (second < 10)
          {
              cout<<"0";
          }
          cout<<second;
          if(hour >= 12)
          {
              cout<<" P.M."<<endl;
          }
          else
          {
              cout<<" A.M."<<endl;
          }
          system("cls");
      }
      system("pause");
      return 0;
}

Is there a way to make the loop terminate on any keystroke?
Is there a better way to make it update so it won't appear flashing?
And...
Is there a better way to clear the screen? (other than system("cls"), which I believe is OS specific.)

Edit: Oh yeah, if you wish to understand my clock, 18000 can be the time_t value of any 12:00 AM, as shown by the comment I just added.

[-=SoKrA=-]

To do the update, all you have to do is add a cout<<"\r" instead of system("cls"). That will make the cursor go back to the beggining of the line, and overwrite anything. I would recomend printing a few spaces after the AM or PM because when you change from 59 minutes to 0 you'll end up with a double M at the end. That is, unless you print double zeroe's.
Don't worry too much about the system("cls"). There are some ways to clear the screen that are compiler specific and I think the time functions are windows only anyway.
Enjoy

[Wick]

Ok, that answers the clearscreen question. Thanks.

Yes, the if statements take care of printing double zeros:

if(minute < 10)
          {
              cout<<"0";
          }
          cout<<minute<<":";
          if (second < 10)
          {
              cout<<"0";
          }

[Wick]

Please forgive the bump. I really could use help on this.

[JaWiB]

Originally posted by adrianwx
I have an example of blocking a continuous loop waiting for keyboard or mouse events in a console in part 5 of my tutorial here . If you're working in real 16 bit DOS, then you'll need to find appropriate API routines.

I'm not sure if it will help in your case, but his tutorials are definitely worth a look...