Category : constants

I have a constructor that accepts a pointer-to-member-function. I have two different functions to be passed in but they fail with some variation of incompatible cv-qualifiers. The constructor parameter is constructor(T (Class::* memfnptr)()) where T and Class are typenames. My two member functions are of the following types when passed as arguments. long int (Encoder::*)() ..

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I saw this answer. https://stackoverflow.com/a/47317853/8106257 But, I don’t satisfying logical const. Is there any other way to sort custom class object with const member variable? I was firstly thought that how about using move constructor but it didn’t work. #include <iostream> #include <vector> #include <algorithm> class City { private: const int _cost; const int _customer; ..

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I need to form a file named "constants.txt", and then use them when defining runge Funtion. Since the constants in the main function cannot be used outside the main function. How can I do about it? Thanks! float runge(float x, float y){ return (-a*x+b*y+c/4.0+e*delta_t);} // where a,b,c,d,e,delta_t are from the file created int main(){ ofstream ..

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I need convert a variable type of const std::shared_ptr<const T> into boost::shared_ptr<T>. In the following scanCallback(), I can not modify the param const std::shared_ptr<const io_adaptor::msg::PandarScan> msg. The msg is very big in memory, which contains large lidar points. PushScanPacket() func’s arg is boost::shared_ptr<io_adaptor::msg::PandarScan>, which I also can not modify its type. The following code does ..

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Is it guaranteed that constexpr function will be evaluated at a compile time, or it’s line inline that compiler can decided to evaluate it at runtime instead? constexpr int Fun(/*maybe some parameters*/); int main() { constexpr int val = Fun(/*maybe some parameters*/); } calculation of val always takes zero time at the runtime? Source: Windows ..

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