Delete Characters from char array

Michael R. Copeland wrote:[color=blue]
> What is a good way to delete 1 character (or several) from a
> character array that's being processed as a "string"? Specifically, I
> have something like:
> char szWork[128];
> ...
> strcpy(szWork, "-1234.5"); // populate the data
> At this point, I'd like to remove the '-' that's in the 1st character
> position (and this example isn't realistic), and I can't see a good way
> to do this: strcpy with a char pointer that points to the 2nd character;
> memmove; I don't know...
> Furthermore, it might be desireable to remove more than 1 character -
> and from within the string's contents. I'd want to extend the
> particular problem above to do that, as well.
> This seems such a common operation (editors, data conversions, etc.),
> that I find it odd I can't find examples (on google, etc.) of how to do
> this.
> I suppose I could use std::string or some advanced "string"
> processing (and I don't know what to use there, either), but that seems
> pretty extreme for this.
> Any thoughts? TIA...[/color]

I don't think a std::string is too "extreme" for this. I think it's a
perfect demonstration of std::string as a better "C string".

I would use std::string myself.

--John Ratliff

> > What is a good way to delete 1 character (or several) from a[color=blue][color=green]
> > character array that's being processed as a "string"? Specifically, I
> > have something like:
> > char szWork[128];
> > ...
> > strcpy(szWork, "-1234.5"); // populate the data
> > At this point, I'd like to remove the '-' that's in the 1st character
> > position (and this example isn't realistic), and I can't see a good way
> > to do this: strcpy with a char pointer that points to the 2nd character;
> > memmove; I don't know...
> > Furthermore, it might be desireable to remove more than 1 character -
> > and from within the string's contents. I'd want to extend the
> > particular problem above to do that, as well.
> > I suppose I could use std::string or some advanced "string"
> > processing (and I don't know what to use there, either), but that seems
> > pretty extreme for this.
> > Any thoughts? TIA...[/color]
>
> I don't think a std::string is too "extreme" for this. I think it's a
> perfect demonstration of std::string as a better "C string".
>
> I would use std::string myself.[/color]

Fair enough. How do I do it to solve the problem(s)? What methods
do I use, and how do I use them?

Michael R. Copeland wrote:[color=blue]
> What is a good way to delete 1 character (or several) from a
> character array that's being processed as a "string"? Specifically, I
> have something like:
> char szWork[128];
> ...
> strcpy(szWork, "-1234.5"); // populate the data
> At this point, I'd like to remove the '-' that's in the 1st character
> position (and this example isn't realistic), and I can't see a good way
> to do this: strcpy with a char pointer that points to the 2nd character;
> memmove; I don't know...
> Furthermore, it might be desireable to remove more than 1 character -
> and from within the string's contents. I'd want to extend the
> particular problem above to do that, as well.
> This seems such a common operation (editors, data conversions, etc.),
> that I find it odd I can't find examples (on google, etc.) of how to do
> this.
> I suppose I could use std::string or some advanced "string"
> processing (and I don't know what to use there, either), but that seems
> pretty extreme for this.
> Any thoughts? TIA...[/color]

Yes, use a std::string, it has all that you require for this.

Ian

In article <MPG.1dd9d512bcf73b109896b4@news.west.cox.net>,
Michael R. Copeland <mrc2323@cox.net> wrote:
[somebody else wrote:][color=blue][color=green][color=darkred]
>> > What is a good way to delete 1 character (or several) from a
>> > character array that's being processed as a "string"? Specifically, I
>> > have something like:
>> > char szWork[128];
>> > ...
>> > strcpy(szWork, "-1234.5"); // populate the data
>> > At this point, I'd like to remove the '-' that's in the 1st character[/color]
>>
>> I would use std::string myself.[/color]
>
> Fair enough. How do I do it to solve the problem(s)? What methods
>do I use, and how do I use them?[/color]

#include <iostream>
#include <string>
using namespace std;

int main ()
{
string szWork = "-1234.5";
szWork.erase(0,1); // starting at position 0, delete 1 character
cout << szWork << endl;
return 0;
}

--
Jon Bell <jtbell@presby.edu> Presbyterian College
Dept. of Physics and Computer Science Clinton, South Carolina USA

> This seems such a common operation (editors, data conversions, etc.),[color=blue]
> that I find it odd I can't find examples (on google, etc.) of how to do
> this.[/color]

It's just too simple ;-). std::string can do it for you, as well as
many other things. Consult the standard library documentation.

The easy way (easy for small things, hard for more complicated), e.g.
to remove the minus sign (without substituting it by something else):

char szWork[128];
strcpy (szWork, "-1234.5");
//...
szWork++;

This just increases the position of the first character. To substitute
the first character by a '+':

*szWork = '+'; // szWork == "+1234.5"

To substitute the 2nd character by a '2':

*(szWork+1) = '2'; // szWork == "+2234.5"

And so on. But remember - std::string gives more elegant solutions and
more possibilities, especially when things get more complicated.


Eckhard

Join Bytes! wrote:[color=blue][color=green]
>> This seems such a common operation (editors, data conversions, etc.),
>> that I find it odd I can't find examples (on google, etc.) of how to do
>> this.[/color]
>
> It's just too simple ;-). std::string can do it for you, as well as
> many other things. Consult the standard library documentation.
>
> The easy way (easy for small things, hard for more complicated), e.g.
> to remove the minus sign (without substituting it by something else):
>
> char szWork[128];
> strcpy (szWork, "-1234.5");
> //...
> szWork++;
>[/color]

Er. szWork is not a modifiable lvalue.

Krishanu

>> char szWork[128];[color=blue][color=green]
>> strcpy (szWork, "-1234.5");
>> //...
>> szWork++;[/color]
>
>Er. szWork is not a modifiable lvalue.[/color]

Ough, sorry - you're right.

It needs to be an dynamically allocated char * if it should be
manipulated:

char *szWork = new char[128];
//...
delete [] szWork;


Eckhard

Join Bytes! wrote:[color=blue][color=green][color=darkred]
>>>char szWork[128];
>>>strcpy (szWork, "-1234.5");
>>>//...
>>>szWork++;[/color]
>>
>>Er. szWork is not a modifiable lvalue.[/color]
>
>
> Ough, sorry - you're right.
>
> It needs to be an dynamically allocated char * if it should be
> manipulated:
>
> char *szWork = new char[128];
> //...
> delete [] szWork;
>
>
> Eckhard
>[/color]

You could also make a char* to szWork and work off that.

char szWork[128];
char* ptr = szWork;
strcpy(szWork, "-1234.5");
// blah blah
++ptr; // *ptr == "1234.5"

--John Ratliff