member

问题 This is my first post so please "Go" easy on me. :) ... I am quite familiar with many traditional programming languages but I am new to Go and having trouble understanding the use of slices and ranges. The program code and comments below illustrate my consternation. Thank you! package main import ( "fmt" "time" ) type myStruct struct { Name string Count int } Wrote my own Mod function because I could not find on in the Go libraries. func modMe(mod int, value int) int { var m int var ret int m

问题 It seems that the following technique for checking the existence of an object member produces an error because the 'bar' parent object hasn't been declared before the check, which means I either have to declare it before the check or use two 'typeof' expressions, either of which would be excess code: var foo = {}, newVal = (typeof foo.bar.myVal !== 'undefined' ? foo.bar.myVal : null ); Error: foo.bar is undefined So, how do you check if a member within an undeclared object exists without

问题 I have a group of classes that have one or more members of the type memberA, memberB, memberC. Not all classes have all the members. I want to create a template that will set the members such as template <typename T> void setAttributes(t & myClass, typeA memA, typeB memB, typeC memC) { myClass.memberA = memA; myClass.memberB = memb; myClass.memberC = memC; } Obviously this will fail at compile time when attempting to instantiate a class that is missing one of the members. Is there a #if or

问题 I have a question about the member variables of static struct in C language. Someone said we can declare a static struct , but in C, struct do not have the static members like class in C++, what does this mean? If I declare a static struct, what is the status of the members variable? can some one help me on this? 回答1: Note that a static struct itself is different from a static member of a struct. While you can declare a static struct variable: static struct MyStruct s; you can't define a

问题 I could be totally wrong here, but as I understand it, C++ doesn't really have a native "pointer to member function" type. I know you can do tricks with Boost and mem_fun etc. But why did the designers of C++ decide not to have a 64-bit pointer containing a pointer to the function and a pointer to the object, for example? What I mean specifically is a pointer to a member function of a particular object of unknown type . I.E. something you can use for a callback . This would be a type which

问题 I'm working with a particle simulation library. The way interactions are added to particles it through the following library function: AddInteraction(ParticleSet particleSet, void(*interaction)(xyz* p, xyz* v)) I now want to pass a member function to AddInteraction. I've understood that this is impossible to do without changing the library function. Changing the library is something I'd like to avoid, but if the change is small I can mail the author of the library and ask for it to be

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Do static members of a class occupy memory if no object of that class is created? Memory Allocation of Static Members in a Class "A class is not considered defined untill its class body is complete, a class can not have data members of its own type. A class can have data members that are pointers/reference to its own type." C++ Primer (Lippman Lajoie) Makes sense. But why is this allowed then ? class justAClass

问题 I come from a Javascript background (where properties can be accessed through both . and [] notation), so please forgive me, but what, exactly, is the difference between the two in Python? From my experimentation it seeems that [] should always be used, both to get the index of a list or set and to get the value from a certain key in a dictionary . Is this correct, and, if not, when do you use a . in Python? 回答1: The dot operator is used for accessing attributes of any object. For example, a

问题 I have been researching, and nothing relevant has come up, so I came here. I am trying to avoid memory leaks, so I am wondering: Say I have class MyClass with member int s a and b , and an int array c , which are filled in a member function: class MyClass { public: int a, b; int c[2]; void setVariables() { a, b = 0; for (int i = 0; i < 2; i++) { c[i] = 3; } } }; int main(int argc, char* argv[]) { MyClass* mc = new MyClass(); mc->setVariables(); delete mc; } Now, after I call delete mc , will

问题 I have this as one of my members of the class 'KeyEvent': private delegate void eventmethod(); And the constructor: public KeyEvent(eventmethod D) { D(); } What I want to do is instead of calling D() there, I want to store that method (D) as a member variable of KeyEvent, so something like: stored_method = D(); And then later in another method of KeyEvent, do something like: stored_method(); How can I do this? 回答1: You pretty much have the code already. Just create a member field of the right