Expert: Joseph Moore - 9/23/2009

Question
how do i declare an ESC button, so that when user presses it the program terminates?

Answer
Hi, Tumelo.

The simplest way to do this is to use the exit function.  The format of the exit function is:

   void exit(int exitCode)

The parameter is the exit code, or the return value given by the application.  Generally, 0 is used to indicate a successful execution and some other value is considered an error.  This is mere convention, and is not a strict guideline.  You can use whatever you like for that parameter.

The exit function immediately ceases execution of the program and returns the value passed in as the exit code.  So, if you have some fatal error or some other immediate exit condition, this is a good function to use to close the program without further execution.

In your case, you say you want an ESC button.  I don't know if you mean a graphical button or if this is a simple console application and you just need to capture the input of some button and use it to close the program.  In either case, whatever method of receiving the escape request, just call the exit function from within the handling code.  For example:

   void escapePressed()
   {
       printf("ESC pressed, halting execution.\n");
       exit(0);
   }

I hope that answers your question.  If you have any further questions, please, do not hesitate to ask.  I am here to help. :)