8 ms·

I knew when I was a C++ dev that any "other languages" was just not serious. Lots of friends who are master in C++ call everything else than C and C++ "scriptin

• dleimbach 13y ago
  Why not: using namespace std; map<int, vector<int>> whatever; It's a lot shorter, actually correct, and it's totally cool to import whole namespaces in a .cpp implementation file where you're likely to actually declare something like that. If you're going to critique the language you should try to learn it first.
• subb 13y ago
  Well to be honest, d = {} is absolutely not equivalent to a map of int to a vector of ints. Sure in javascript, you can indeed use an object as a map, but you are lacking the type safety that the C++ version provide and all the nice API. Also, in C++11, you can shorten it with auto : auto whatever = new std::map<int, std::vector<int>>(); and to be fair with the js, if you want it as short as possible, you could use a using namespace statement for std (although not really recommended) : auto whatever = new map<int, vector<int>>(); or maybe not use new : map<int, vector<int>> whatever; I don't think it's that bad. But sure, any dynamic language will be less verbose that a static language because, well, you are removing information...
• zokier 13y ago
  C++11 brought type inference so these days it would be either auto whatever = new std::map<int, std::vector<int>>(); or std::map<int, std::vector<int>> whatever; depending on if you want heap or stack allocated variable, stack allocation usually being preferred as the default solution (and thus being the tersest form). But lets look a bit deeper why C++ is more verbose in this case. One central reason is the idea that standard library should not be special/privileged in the language syntax. The upside from that is that almost all syntax sugar can be applied to user defined types. A relevant example would be uniform initializer lists in C++11, which allow you to write eg. std::vector<int> foo {1,2,3}; but also MyFunkyDatastructure bar {1,2,3}; as long as suitable constructors are defined. In comparison afaik in Python you can not define a class that can be initialized with sugared syntax. The theme of non-privileged standard library also extends to global namespace pollution. In C++ stdlib does not get to reserve names at global namespace, which leads slightly increased verbosity (std:: -prefixes or using-statements). So when you ask why you cant make a map/dict in C++ with just 'd = {}', know that there are actually good reasons for (some/most) of the verbosity. The tradeoffs might make it less suitable in your usecases, but there is no absolute/general superiority in either way.
  • d0m 13y ago
    >> know that there are actually good reasons for (some/most) of the verbosity. This is why I talked about the philosophy of the language. I wasn't arguing about whether it was good or bad. That being said, for my own use cases, verbosity is a big deal. >> In C++ stdlib does not get to reserve names at global namespace, which leads slightly increased verbosity (std:: -prefixes or using-statements). I understand and agree, but you'd have to agree with me that if you start naming your classes Map and Vector, you're looking for problems ;-)
• cldr 13y ago
  This isn't really a fair criticism because: 1. You picked probably the most verbose way to do it. 2. It's not valid C++ because you're assigning a pointer to a value. 3. Idiomatic C++ doesn't use `new` explicitly anyway 4. The `d = {}` of Python is not really equivalent. My feeling is that python gains brevity in exchange for putting a heavier mental load on the programmer, which is manageable for small programs but becomes unwieldy for larger ones.
  • anonymoushn 13y ago
    Does idiomatic C++ do heap allocations with malloc then?
    • pkolaczk 13y ago
      No. Idiomatic C++ allocates everything at compile time by means of template metaprogramming magic (just joking).
      • he_the_great 13y ago
        No that is D and it is with CTFE. Also joking... mostly.
    • cldr 13y ago
      Idiomatic C++ would allocate everything possible on the stack, and if that wasn't possible, use `make_shared`/`make_unique`. So maybe I will change it to say "doesn't use `new` directly".
• WalterBright 13y ago
  In D it would be: int[int] whatever;
  • cldr 13y ago
    Actually wouldn't it be int[][int] whatever; ? Because I think we should be getting an array out whenever we do whatever[1] and not just an int.
    • keyle 13y ago
      (You were questioning the language designer there)
      • cldr 13y ago
        I know, I think he misread the C++ code.
    • WalterBright 13y ago
      Yes, you're right.
• nly 13y ago
  This works just fine: map<int, vector<int>> d = {{0, {1,2,3,4,5}}, {1, {6,7,8,9,10}}};