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Should focus on getting rid of undefined behavior.
Should focus on getting rid of undefined behavior.
What problem do you believe is presented by undefined behavior?
It violates the principle of least surprise. You don’t expect the compiler to delete your bounds checking etc.
The way c and c++ define and use UB is like finding an error at compile time and instead of reporting it, the compiler decides to exploit it.
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
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::mapto access the element associated with a key, you need to either useatand handle an exception if no such key exists, or usefind.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)
