Contolling istringstream input

[Ruben]

I want to get from stdin a string that might look like any of these three
options

99
99lb
99 lb
but if a number isn't at the beginning for the string, or is the left over
letters aren't either lb or kg, for an error to be be throw.

I can't seem to find a reasonable means of doing this.

If can do a
cin >some_previous_double;
buf[] = 512;
istringstream stream1;
cin.ignore();
cin.getline(buf, 512);
try{
stream1.str(descr);
if (!(stream1>>hgt_))
{
errormsg.append(descr);
throw errormsg;
}
if(!(stream1>>unit_))
{
errormsg.append(descr);
throw errormsg;
}
if( unit_ == "meters"|unit_ == "meter" || unit_ == "m" \
|| unit_ == "mt"|| unit_ == "mtr"|| unit_ == "mt")
{
unit_ = "in";
hgt_ = hgt_ * 39.37;

}else if( unit_ == "in" || unit_ == "inch" || unit_ == "i"\
|| unit_ =="inches" ){
unit_ = "in";
}else{
errormsg.append(":You entered =>");
errormsg.append(descr);
throw errormsg;
}
}
catch (string errormsg){
cout << "Error: Units error - can\'t determine type\n" << errormsg;
cout << "\n" << "Setting Height to 68 inches\n";
hgt_ = 68;
unit_ = "in";
}


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[James Kanze]

On Sep 17, 1:03 am, Ruben <[e-mail]:

I want to get from stdin a string that might look like any of
these three options

99
99lb
99 lb

but if a number isn't at the beginning for the string, or is
the left over letters aren't either lb or kg, for an error to
be be throw.

I can't seem to find a reasonable means of doing this.

boost::regex matcher( "(\\d+)(?:[[:blank:]]*(lb|kg))?$" ) ;

The first capture contains the number, the second is either
empty, or contains the "lb" or the "kg".

(BTW: your signature is incorrectly delimited, and is longer
than what is generally considered acceptable. The delimiter
should be a line containing exactly "-- ", and nothing else, and
four lines is generally considered the maximum acceptable.)

--
James Kanze (GABI Software) email:ja*********@gmail.com
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