error: redefinition of class

You should structure your code between .h (headers) and .cpp files (implementation). You should include header files: .h Never include .cpp files. (Unless you know what you do, and that would be in really rare cases). Otherwise you’re ending compiling several times your class, and you get the error your compiler is telling you: ‘redefinition of class…’ An additional … Read more

C++ error: no matching constructor for initialization of

In the line you are trying to invoke the default constructor of Rectangle. The compiler does not generate such a default constructor anymore, because your Rectangle has a user defined constructor that takes 2 parameters. Therefore, you need to specify the parameters, like The error I get when compiling your code is: Rectangle.cpp:8:15: error: no matching function for … Read more

Why am I getting this redefinition of class error?

You’re defining the class in the header file, include the header file into a *.cpp file and define the class a second time because the first definition is dragged into the translation unit by the header file. But only one gameObject class definition is allowed per translation unit. You actually don’t need to define the … Read more

invalid use of non-static member function

You must make Foo::comparator static or wrap it in a std::mem_fun class object. This is because lower_bounds() expects the comparer to be a class of object that has a call operator, like a function pointer or a functor object. Also, if you are using C++11 or later, you can also do as dwcanillas suggests and use a lambda function. C++11 also has std::bind too. Examples:

Fastest way to check if a file exist using standard C++/C++11,14,17/C?

Well I threw together a test program that ran each of these methods 100,000 times, half on files that existed and half on files that didn’t. Results for total time to run the 100,000 calls averaged over 5 runs, Method Time exists_test0 (ifstream) 0.485s exists_test1 (FILE fopen) 0.302s exists_test2 (posix access()) 0.202s exists_test3 (posix stat()) 0.134s The stat() function provided the … Read more

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