Re: Splitting a String with 2 input variables, "beginstr" and "endstr"

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 3 Sep 2008 01:52:28 -0700 (PDT)
Message-ID:
<3616eb3a-7753-4965-93db-bbecccd2a26e@j22g2000hsf.googlegroups.com>
On Sep 2, 9:39 pm, kevineller...@gmail.com wrote:

On Sep 2, 2:07 pm, Erik Wikstr=F6m <Erik-wikst...@telia.com> wrote:

On 2008-09-02 19:31, kevineller...@gmail.com wrote:

I want to make a split string function, but it's getting
complicated.

What I want to do is make a function with a String,
BeginStr and an EndStr variable, and I want it to return
it in a char array.

For example:

char teststr[255];
strcpy(teststr, "test:blah;");

char returned_string[255];
strcpy(returned_string, splitstring(teststr, "test:", ";"));

and it returned_string would = blah

can someone help me?


Sure, first dump the char arrays and use std::string. Then
read up on std::string::find() and std::string::substr().
Start by finding BeginStr and get a substring of everything
after it, then find EndStr in that and return everything in
front of it.


Ok I did that, but my string here is:

"test1=test1; test2=test2;"

and it finds test2, but it only finds the FIRST ";", so it's
saying that the EndStr is before the BeginStr, and it doesn't
do this correctly, any remedy?

I'm sorry I didn't include that I needed to parse a whole line
of these from a text file.


And you still haven't specified the format of that line, or what
you're trying to do. If the goal is to create some sort of set
of attribute value pairs, with /; */ as a separator between each
entry, and /:/ as separator between the attribute and its value,
this is easiest done using tr1::regex and a loop, but even
without regex:

    std::map< std::string, std::string >
    parseAttributeValuePairs(
        std::string const& source )
    {
        typedef std::string::const_iterator
                            TextIter ;
        typedef std::map< std::string, std::string >
                            Result ;
        Result result ;
        TextIter current = skipSpaces( source.begin() ) ;
        TextIter end = source.end() ;
        while ( current != end ) {
            TextIter separ = std::find( current, end,
':' ) ;
            if ( separ == end ) {
                // Error handling here...
            }
            std::string attr( current, separ ) ;
            TextIter termin = std::find( separ + 1, end,
';' ) ;
            if ( termin == end ) {
                // Error handling here...
            }
            std::string value( separ + 1, termin ) ;
            result.insert( Result::value_type( attr, value ) ) ;
            current = skipSpaces( termin + 1 ) ;
        }
        return result ;
    }

(Note that as written, the "error handling" must throw, since
continuing in the loop in case of an error will result in
undefined behavior. A better solution might involve skipping
the entry, and some sort of resynchronization, with memorization
of the error(s), and returning a Fallible.)

--
James Kanze (GABI Software) email:james.kanze@gmail.com
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