Thread: I have a problem with C + +.

Hello ..


I have a problem with C + +.

Look at this small program ...

Code:

#include <iostream>
#include <windows.h>

using namespace std; 


main ()
{
     
for ( int i = 0 ; i < 50 ; i ++ )
{

cout << i << endl ;

Sleep(1000);

}

cout << "Done! ";

getchar ();
getchar ();

}

How to Make this program when enter Character 's' exit from loop .

without using cin or break . ??

Can you use other functions, like getline()?
You don't need break. You can do something like

Code:

i < 50 && c != 's'

Originally Posted by OOP_C++

How to Make this program when enter Character 's' exit from loop. without using cin or break . ??

The real question is: Why do you have such superficial requirements?

I mean, when I press the letter S at any time directly out of the loop .. I hope you write the program to understand

Originally Posted by OOP_C++

I mean, when I press the letter S at any time directly out of the loop .. I hope you write the program to understand

Right. So, again, why exactly can't 'cin' nor 'break' be used? Just a whim, or what? Anyway, post #2 basically answers your question, I think.

Work with something like this using GetAsyncKeyState();

Code:

#include <iostream>
#include <windows.h>

using namespace std;

int main()
{
     int i = 0;
     while(!GetAsyncKeyState(0x53))
     {
           ++i;
           cout << i << endl;
           Sleep(1000);
     }
     return 0;
}

Originally Posted by C_Sparky

Work with something like this using GetAsyncKeyState();

Code:

#include <iostream>
#include <windows.h>

using namespace std;

int main()
{
     int i = 0;
     while(!GetAsyncKeyState(0x53))
     {
           ++i;
           cout << i << endl;
           Sleep(1000);
     }
     return 0;
}

it is good .

Thank you very much

but , Can you explain to me this function in detail . ((GetAsyncKeyState(0x53))

And how to used in for loop ??

Look GetAsyncKeyState up on msdn, it's a WinAPI function and should be well documented there. Cin is better though, because it is portable, anything in WinAPI is not.

cin is not asynchronous though
There are other ways past GetAsyncKeyState(), but it seems like a good solution here.
The other way to go is to use signals. When 's' is pressed it will send a signal. The signal handler will automatically called and it will result on breaking the loop.

This can be done by throwing an exception maybe. Or setting a flag and each line in the loop being if(flag) else break. Or more drastically killing the program.