Question

Earlier today (actually yesterday due to my time-zone) I was attempting a programming interview using Visual Studio 2012 for C++ on Interview Street (which uses g++).

To be brief, I came across several compilation errors¹ when I was using

#include <cstring>

which was provided by the skeleton code in one of the question, and after turning to

#include <string>

all compilation errors magically disappeared.

However, upon submission to Interview Street, I had to add c back; otherwise I got compilation errors.

It was the first time I was bitten by non-standardization….

My question is: what inside <string> and <cstring> took me (precious) more than half an hour?

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¹ For anyone who is curious:

One error by Visual Studio 2012 if using <cstring> is:

error C2338: The C++ Standard doesn’t provide a hash for this type.

in

c:\program files (x86)\microsoft visual studio 11.0\vc\include\xstddef

possibly for string as key in unordered_map

One error by g++ if using <string> is:

‘strlen’ was not declared in this scope

Answer 1

The cstring header provides functions for dealing with C-style strings — null-terminated arrays of characters. This includes functions like strlen and strcpy. It’s the C++ version of the classic string.h header from C.

The string header provides the std::string class and related functions and operators.

The headers have similar names, but they’re not really related beyond that. They cover separate tasks.