How to avoid invalid argument exception in case of string to integer conversion

Question

In C# there are try functions to avoid exceptions e.g. Int.TryParse(). I am looking for a similar function for C++ as a replacement for std::stoi().

you can use [this](https://stackoverflow.com/questions/36492029/c-function-call-wrapper-with-function-as-template-argument) to wrap calls to any function and return false if you catch exception — Krzysztof Skowronek, Mar 16 '18 at 16:20
If you want to avoid exceptions test first: https://stackoverflow.com/questions/437882/what-is-the-c-sharp-equivalent-of-nan-or-isnumeric — Jay, Mar 16 '18 at 16:21
@Carl: no I want to avoid id, e.g. in case of an empty string it should return 0 an not throw an exception. — Werner, Mar 16 '18 at 16:38
I use the C++ versions of the good ol C `strto` family of functions. [Here's documentation for one of them](http://en.cppreference.com/w/cpp/string/byte/strtol). The rest are linked at the bottom of the page just below the usage example. — user4581301, Mar 16 '18 at 16:49
@Neil: thanks, you are right, I failed to see that strtol never throws an exception but std:stol does. However is there also a similar std function ? — Werner, Mar 16 '18 at 16:51

score 1 · Accepted Answer · answered Mar 16 '18 at 16:58

1

C++ like way:

unsigned long value;
std::istringstream s(data);
if(s >> value)
{
     // possibly check, if the stream was consumed entirely...
}

What I like about this approach: if using cstdint's types, you do not need to worry about if you use the correct type with the correct function...

answered Mar 16 '18 at 16:58

Aconcagua

1 Answers1