Solved

how to let a prognamm stop in random?

Posted on 1998-01-13
10
195 Views
Last Modified: 2010-04-10
Dear Sir:
  I have written a prognamm.I want to add a function let it
stop in random,I mean when I pressa key it should stop.
When I press another key it should run again.How to do?
Thanks
0
Comment
Question by:youngest
  • 6
  • 4
10 Comments
 
LVL 22

Accepted Solution

by:
nietod earned 100 total points
ID: 1178244
answer comming
0
 
LVL 22

Expert Comment

by:nietod
ID: 1178245
basically it is impossible to stop (suspend) a program.  (actually it is often possible to suspend a program on a multi-tasking operating system.  But how to do so is system-dependant and not what you want.)

Since it is impossible--fake it.

don't stop the program, instead make it appear stopped by having it execute a loop that does (almost) nothing.  Actually the loop can't do nothing or it will never end.  The loop should look for the key press that should allow the program to continue.

next problem, where do you put the loop?

That depends on you program.  If you program has a single central procedure for obtaining user input (like most windows programs, as well as others) then you can put the code to start the loop there.  Otherwise, you may need to alter the code at every location that does user input.

I can't provide more help without knowing more about your program its purpose and its design.  

If you need more, post some more information.
0
 
LVL 22

Expert Comment

by:nietod
ID: 1178246
I see you accepted the answer, but I suspect that (as it is) it wasn't enough.  Do you need more help?
0
Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

 

Author Comment

by:youngest
ID: 1178247
Thank you for helping me.
Can you help me?perhaps TSR can be solved this problem?
Do you think ?

0
 
LVL 22

Expert Comment

by:nietod
ID: 1178248
A TSR could be used to suspend a DOS program.  But it seems like a very poor solution.  It is very system dependent.  What is it exactly that you are trying to do?  
0
 

Author Comment

by:youngest
ID: 1178249
Thank you for helping me.I plan to write a demo prognamm,I should let it stop when it is needed to stop.then press any key it should continue to run .
0
 
LVL 22

Expert Comment

by:nietod
ID: 1178250
But why can't the program itself look for the key and enter a wait loop whent he key is pressed?  Doesn't that seem like a more natural design than envoking a TSR to suspend the program?  It is also more portable and as well as more extensible.
0
 

Author Comment

by:youngest
ID: 1178251
In BC++,how to realize stop?use getch()?I tried to do but failed.
Can you tell me?The computer can't correspond with this keyboard
interrupt.

0
 
LVL 22

Expert Comment

by:nietod
ID: 1178252
You do not mean keyboard interrupt?  right.  I don't think you need to hook the keyboard interrupt and if you do you don't use getch().

you could do something like the following which holds up a loop whenever 'P' is typed.  The loop continues again when 'P' is typed again.

while (NotDoneDoingSomething())
{
   DoALittleSomething()
   if (_kbhit()) // If a key has been typed, then
       if (_getch() == 'P')
          while (_getch() != 'P');
}

Does this help?  I'm having a hard time understanding your situation.  If this doesn't help explain in more detail what it is your trying to do.
0
 

Author Comment

by:youngest
ID: 1178253
It IS GOOD!jUST What I need!Thank you!
0

Featured Post

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Written by John Humphreys C++ Threading and the POSIX Library This article will cover the basic information that you need to know in order to make use of the POSIX threading library available for C and C++ on UNIX and most Linux systems.   [s…
  Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and …
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.
The viewer will be introduced to the member functions push_back and pop_back of the vector class. The video will teach the difference between the two as well as how to use each one along with its functionality.

808 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question