Delete Characters from char array

[Michael R. Copeland]

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...

 

[John Ratliff]

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...

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

 

[Michael R. Copeland]

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.
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...

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.

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

 

[Ian]

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...

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

Ian

 

[Jon Bell]

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

I would use std::string myself.

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

#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;
}

 

[ecky-l]

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.

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

 

[Krishanu Debnath]

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.

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++;

Er. szWork is not a modifiable lvalue.

Krishanu

 

[ecky-l]

char szWork[128];

Er. szWork is not a modifiable lvalue.

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

 

[John Ratliff]

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

Er. szWork is not a modifiable lvalue.

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

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