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C++ Should Be C++ (www.open-std.org)
submitted 2 years ago by [M] to c/cpp@programming.dev
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[–] 2 points 2 years ago* (1 child)

I am trying C++ for this year's advent of code. The most asinine thing i encountered is that the bracket operator on std::map writes 0 value if the key is not found. So your code doesn't compile if you declare a const map or a const map reference as a function parameter. Compiler fails with "discards const qualifier on argument".

I mean, wtf?

Edit: this is probably true for other STL containers

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  • [–] [S] 1 point 2 years ago (1 child)

    The most asinine thing i encountered is that the bracket operator on std::map writes 0 value if the key is not found.

    That's a "you're using it wrong" problem. The operator[] is designed to "Returns a reference to the value that is mapped to a key equivalent to key, performing an insertion if such key does not already exist. "

    The "0 value" just so happens to be the result you get from a default initializer whose default initialization corresponds to zero-initialization.

    If you want to use a std::map to access the element associated with a key, you need to either use at and handle an exception if no such key exists, or use find.

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  • [–] 3 points 2 years ago*

    My point is that the design is wrong. Nobody expects [] as lvalue to update a value. Your argument is descriptive, mine is prespcriptive. I am saying that the C++ committee is wrong on this one (or whoever designed it this way)

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