declaration

I have been writing java for a while, and today I encountered the following declaration: public static void main(String... args) { } Note the "dot dot dot" in the array declaration, rather than the usual bracket []. Clearly it works. In fact I wrote a small test and verified it works. So, I pulled the java grammar to see where this syntax of argument declaration is, but did not find anything. So to the experts out there, how does this work? Is it part of the grammar? Also, while I can declare function like this, I can't declare an array within a function's body like this. Anyway, do you know

My project consists of only two source files: a.cpp: const int n = 8; b.cpp: extern const int n; int main() { // error LNK2001: unresolved external symbol "int const n" (?n@@3HB) int m = n; } I know there are several methods to make it work; however, I just wonder WHY it does't work? It's because const implies internal linkage by default, so your "definition" isn't visible outside of the translation unit where it appears. In this case, by far the best solution is to put the declaration ( extern int const n; ) in a header file, and include that in both a.cpp and b.cpp . The linkage is

In the reference section of Apple's docs there's lots of instances of this sort of thing: func runAction(_ action : SKAction!) The Objective-C 'equivalent' of this is: - (void)runAction:(SKAction *) action It strikes me that it's probably important that (in the Swift reference) there's a space after the underscore and "action" is written in italics. But I can't figure out what this is trying to convey. So perhaps the question is... is there a reference for the conventions used in the references? -- here's the page I'm referencing in this reference to the underscore use: https://developer.apple

class my_class { ... my_class(my_class const &) = delete; ... }; What does = delete mean in that context? Are there any other "modifiers" (other than = 0 and = delete )? Prasoon Saurav Deleting a function is a C++11 feature : The common idiom of "prohibiting copying" can now be expressed directly: class X { // ... X& operator=(const X&) = delete; // Disallow copying X(const X&) = delete; }; [...] The "delete" mechanism can be used for any function. For example, we can eliminate an undesired conversion like this: struct Z { // ... Z(long long); // can initialize with an long long Z(long) =

I have a crazy question about Java switches. int key = 2; switch (key) { case 1: int value = 1; break; case 2: value = 2; System.out.println(value); break; default: break; } Scenario 1 - When the key is two it successfully print the value as 2. Scenario 2 - When I'm going to comment value = 2 in case 2: it squawks saying the The local variable value may not have been initialized . Questions : Scenario 1 : If the execution flow doesn't go to case 1: (when the key = 2 ), then how does it know the type of the value variable as int ? Scenario 2 : If the compiler knows the type of the value