How is factorial computed?
say there is a function to calculate factorial(n) Does factorial(7) creates 7 function object for each of n from 1 to 7 and use those values when ever necessary (for factorial(8) as like factorial(7)*8) ...
function-object
In C++ what does it mean for a compiler to "inline" a function object?
In the wikipedia article about function objects it says such objects have performance advantages when used with for_each because the compiler can "inline" them. I'm a bit foggy on exactly what this means in this context... or any context I'm embarrassed to say. Thanks for any help! ...
When do you use function objects in C++?
I see function objects used often together with STL algorithms. Did function objects came about because of these algorithms? When do you use a function object in C++? What is its benefits? ...
function objects versus function pointers
Hi All, I have two questions related to function objects and function pointers, Question : 1 When I read the different uses sort algorithm of STL, I see that the third parameter can be a function objects, below is an example class State { public: //... int population() const; float aveTempF() const; //....
understanding Functors in STL
quoting from "The C++ Standard Library" by N M Jousttis, Section 5.9 #include < iostream> #include < list> #include < algorithm> using namespace std; //function object that adds the value with which it is initialized class AddValue { private: int the Value; //the value to add public: //constructor initializes t...
templates and function objects - c++
i have a problem with this class. the goal is to make the main function work properly. we were supposed to implement the "And" function object so that the code will work. i can't find what is the problem with our solution. (the solution start and end are marked in comments in the code before the "main" function) can you please help? than...
Declaring and defining a function object inside a class member function
Hello to everyone, I wonder if and how it is possible to define a function object inside a classes member function to use it directly with, for example, the std::transform function. I know the example is a bit stupid, it's just to show the problem I'm confronted with. File "example.h" class Example { public: //.. constructor and...
Access result type of a function template parameter in the template?
Given the following template: template<class T> class Container { private: boost::function<T> f; }; ... and its instantiation, perhaps as follows: Container<bool(int, int)> myContainer; , is there a way to access the return type of the function description and compile conditionally against it? For example, if the caller...
How does template parameter of std::function work? (implementation)
In Bjarne Stroustrup's home page (C++0x FAQ): struct X { int foo(int); }; std::function<int(X*, int)> f; f = &X::foo; //pointer to member X x; int v = f(&x, 5); //call X::foo() for x with 5 How it works? How std::function calls foo member function? According to the template parameter int(X*, int), is &X::foo converted from the memb...
parsing JSON - eval() or function object?
To parse JSON, I believe the best method is to use native JSON support in browsers. I was looking for a good way to parse JSON in cases where native JSON support is not available. When i looked at the code in http://www.json.org/json2.js, what i understood was it first checks whether the data is valid JSON using the regex: if (/^[\],:...
Detailed difference between functor's call and function call ?
The key reason this works is that for_each () doesn’t actually assume its third argument to be a function. It simply assumes that its third argument is something that can be called with an appropriate argument. A suitably defined object serves as well as – and often better than – a function. For example, it is easier to ...