On 2007-04-25 11:34, Steve555 wrote:
Hi,
In a function that erases part of a string, the compiler sometimes
gives this error:
terminate called after throwing an instance of 'std::out_of_range'
what(): basic_string::erase
I can guess, then, that I'm erasing outside the strings length, but I
can not find the bug:
for(long i=0; i<str.length()-1; i++)
{
if( str[i] == '[' && str[i+1] == ']' )
str.erase(i, 2);
}
Maybe someone can see the problem in this case, but I'm also
interested in generally learning how to use these exceptions.
How do I use 'out_of_range' and 'what' in my source code so I can put
a breakpoint in to the debugger when this error occurs?
out_of_range is one of the exceptions found in <stdexcept> and is a
class derived from std::exception (found in <exception>). To handle
exceptions you put the stuff that might throw in a try-block and then
use catch() to catch the exceptions:
try {
/* Code that can throw */}
catch (std::out_of_range& e) {
std::cout << "Out of range: " << e.what() << "\n";}
catch (std::exception& e) {
std::cout << "Some other exception: " << e.what() << "\n";
}
This will first see if it's a out_of_range exception that has been
thrown, and if it is it will be handled as such. If not it will try to
catch it as a std::exception and handle it as such.
Notice though that there's no need for an exception to be derived from
std::exception, anything can be thrown, even ints doubles and such. You
should really read up on them in your book, there's more to know.
BTW, what debugger are you using that does not break on an unhandled
exception?
--
Erik Wikstr=F6m
too).
I'm using Apple's XCode. It does indeed break on exceptions, what I