Re: [Dev-C++] A very singular problem in Cpp

[Per W. <pw...@ia...>]

The overhead might be expensive for an application that needs to use
system("pause") in a loop. But as a final call before hanging there,
waiting for the execution to end, you can ignore the cost. Even in a
global perspective, the inefficiency is minimal compared to applications
written in some other languages.

/pwm

On Mon, 2 Apr 2007, Jonathan Winterflood wrote:

> Indeed, in a general case, (and esp. in Unix), there are tools that are
> easily used this way (and are definitely designed to).
> In the case of system('pause'), however, it's really an overkill, since the
> command only does something trivial to do in code (plus the overhead...)
>
> Jonathan
>
> On 4/2/07, Per Westermark <pw...@ia...> wrote:
> >
> > Calling system functions isn't necessarily extra unsafe, and it isn't as
> > simple as being bad if the OS does some of the work.
> >
> > When developing for unix, the majority of all command-line utilities are
> > intended for interaction with other applications. Either externally - by
> > letting the user piping data between the applications - or internally, by
> > making use of popen() to directly read the output of other applications.
> >
> > It should be noted, that in an M$ world, it is practically impossible to
> > write a truly portable application. Why? M$ have decided to rename a large
> > number of standard C functions - giving them an initial '_' character in
> > the name.
> >
> > /Per W
> >
> > On Mon, 2 Apr 2007, Jonathan Winterflood wrote:
> >
> > > Indeed, system('pause') is rather messy (plus it's not really portable)
> > > I usually do a system('pause') as a quick fix in the early stages of
> > setting
> > > up a program, I guess I'll use cin.get() from now on :)
> > >
> > > This would make the program so:
> > >
> > > #include <iostream>
> > > using namespace std;
> > > int main()
> > > {
> > >   //say hello :)
> > >   cout<<"Hello World!\n";
> > >
> > >   //wait for user keypress
> > >   int pressed = cin.get();
> > >
> > >   //ignores an extra keypress
> > >   cin.ignore();
> > >
> > >   /*
> > >     do some more things here
> > >   */
> > > }
> > >
> > > But why should I ignore an extra character in the input, since the
> > cin.get()
> > > will eat the key the user pressed?
> > > could it be a '\n' vs. '\r\n' issue ?
> > >
> > > Jonathan
> > >
> > > On 4/2/07, Amy...@ao... <Amy...@ao...> wrote:
> > > >
> > > >  you really should not use system calls in a program unless you really
> > > > need it. They are unsafe, and it sort of gets the OS to do the work
> > for you.
> > > > It is always safer and better practice to use cin.get() instead of
> > > > system("pause")
> > > >
> > > > Yiu can add cin.ignore() under cin.get() if you use cin in the program
> > as
> > > > an input object, but not all compilers need this, the mingw one does
> > however
> > > >
> > >
> >
> >
>
>
> --
> <Morpheus> linux, c'est une question de VI ou de MORE
>