Creating a text editor in C

[siliconwafer]

I want to create a text editor using C.
I want user to enter text freely without worring about what's gonig
inside.
I tried some combinations of fgets,fgetc with realloc and stdin as
poniter.Bute can't do it successfully.
What can be a way?
How are editors created normally?
If there are some functions in C ,welcomed.
thanks.

[Becker]

Maybe you'd like to read Richard Stallman's
<<EMACS: The Extensible, Customizable Display Editor>>
at:
http://www.gnu.org/software/emacs/emacs-paper.html

[Richard Heathfield]

siliconwafer said:

I want to create a text editor using C.
I want user to enter text freely without worring about what's gonig
inside.
I tried some combinations of fgets,fgetc with realloc and stdin as
poniter.Bute can't do it successfully.
What can be a way?
How are editors created normally?
If there are some functions in C ,welcomed.
thanks.

Using only ISO C, you can write a line editor reasonably easily. But if you
want fully-addressable screen I/O, fancy graphics, and so on, you'll need
to use libraries specific to your implementation (although two or three
cross-platform libraries do exist which can, at least, make your code
portable across the more popular desktop OSs).

I suggest you start off by deciding how you wish to represent the text
internally - a linked list of line buffers is one possible option, but by
no means the only one. You should then be able to write a suite of
functions to manage and manipulate this storage. So far, you can stay
entirely within the remit of ISO C. Then, if you value flashy graphics over
portability, I suggest you move your enquiries to a newsgroup dealing with
programming for your platform. If you value portability over flashy
graphics, this is probably a better newsgroup for your questions.

Have a go, see how far you get, ask if you get stuck, and be ready to post
your best-effort code.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

[siliconwafer]

How does one create a 1 line editor with dynamic allocationi?
Say,If user types only 3 characters,I want to reserve only 3 locations
for it.
With static allocation,I can take an array of 640 characters,but it
would be inefficient
if user types only 3 characters per line.
Any hints?
Richard Heathfield wrote:

siliconwafer said:

I want to create a text editor using C.
I want user to enter text freely without worring about what's gonig
inside.
I tried some combinations of fgets,fgetc with realloc and stdin as
poniter.Bute can't do it successfully.
What can be a way?
How are editors created normally?
If there are some functions in C ,welcomed.
thanks.

Using only ISO C, you can write a line editor reasonably easily. But if you
want fully-addressable screen I/O, fancy graphics, and so on, you'll need
to use libraries specific to your implementation (although two or three
cross-platform libraries do exist which can, at least, make your code
portable across the more popular desktop OSs).

I suggest you start off by deciding how you wish to represent the text
internally - a linked list of line buffers is one possible option, but by
no means the only one. You should then be able to write a suite of
functions to manage and manipulate this storage. So far, you can stay
entirely within the remit of ISO C. Then, if you value flashy graphics over
portability, I suggest you move your enquiries to a newsgroup dealing with
programming for your platform. If you value portability over flashy
graphics, this is probably a better newsgroup for your questions.

Have a go, see how far you get, ask if you get stuck, and be ready to post
your best-effort code.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

[Ed Prochak]

siliconwafer wrote:

How does one create a 1 line editor with dynamic allocationi?
Say,If user types only 3 characters,I want to reserve only 3 locations
for it.
With static allocation,I can take an array of 640 characters,but it
would be inefficient
if user types only 3 characters per line.
Any hints?

look up malloc()

(that should be a sufficient hint)

HTH,
ed

[tatimmer]

siliconwafer wrote:

I want to create a text editor using C.
I want user to enter text freely without worring about what's gonig
inside.
I tried some combinations of fgets,fgetc with realloc and stdin as
poniter.Bute can't do it successfully.
What can be a way?
How are editors created normally?
If there are some functions in C ,welcomed.
thanks.

The "pec" multi-line edit control is written in C for Windows. It uses
malloc on each keystroke and connects the blocks with a double link
list.

www.ticon.net/~tatimmer/programming.htm

TomT

[Randy Howard]

siliconwafer wrote
(in article
<11************ **********@f14g 2000cwb.googleg roups.com>):

How does one create a 1 line editor with dynamic allocationi?
Say,If user types only 3 characters,I want to reserve only 3 locations
for it.
With static allocation,I can take an array of 640 characters,but it
would be inefficient
if user types only 3 characters per line.

This is 2005. Are you really worried about maximizing memory
information for a single line of text?

If you are, (or if your professor is), then lookup the malloc()
documentation on your system.
--
Randy Howard (2reply remove FOOBAR)
"The power of accurate observation is called cynicism by those
who have not got it." - George Bernard Shaw

[Keith Thompson]

"Becker" <we*******@devh r.com> writes:

Maybe you'd like to read Richard Stallman's
<<EMACS: The Extensible, Customizable Display Editor>>
at:
http://www.gnu.org/software/emacs/emacs-paper.html

First, please provide context when you post a followup.
Read <http://cfaj.freeshell. org/google/>.

Second, I don't think emacs is a good starting point for a C beginner
who wants to write a text editor. Emacs is practically an operating
system. A simpler line-oriented editor like "ed" would be a much
better place to start.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Keith Thompson]

Randy Howard <ra*********@FO OverizonBAR.net > writes:

siliconwafer wrote
(in article
<11************ **********@f14g 2000cwb.googleg roups.com>):

How does one create a 1 line editor with dynamic allocationi?
Say,If user types only 3 characters,I want to reserve only 3 locations
for it.
With static allocation,I can take an array of 640 characters,but it
would be inefficient
if user types only 3 characters per line.

This is 2005. Are you really worried about maximizing memory
information for a single line of text?

If you are, (or if your professor is), then lookup the malloc()
documentation on your system.

If a 1-line editor is to be the basis for a multi-line editor, it
certainly makes sense to conserve memory, so you can edit large files
without using an order of magnitude more memory than necessary. And
it makes sense to implement the allocation code at an early stage of
the project.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Randy Howard]

Keith Thompson wrote
(in article <ln************ @nuthaus.mib.or g>):

Randy Howard <ra*********@FO OverizonBAR.net > writes:

siliconwafer wrote
(in article
<11************ **********@f14g 2000cwb.googleg roups.com>):

How does one create a 1 line editor with dynamic allocationi?
Say,If user types only 3 characters,I want to reserve only 3 locations
for it.
With static allocation,I can take an array of 640 characters,but it
would be inefficient
if user types only 3 characters per line.

This is 2005. Are you really worried about maximizing memory
information for a single line of text?

If you are, (or if your professor is), then lookup the malloc()
documentation on your system.

If a 1-line editor is to be the basis for a multi-line editor, it
certainly makes sense to conserve memory, so you can edit large files
without using an order of magnitude more memory than necessary.

I don't disagree with that, but I was referring to the context
from upthread, wherein this was a (single) line editor, to meet
clc standard conformance, etc.
--
Randy Howard (2reply remove FOOBAR)
"The power of accurate observation is called cynicism by those
who have not got it." - George Bernard Shaw