I have always wondered if, in general, declaring a throw-away variable before a loop, as opposed to repeatedly inside the loop, makes any (performance) difference? A (quite pointless) example in Java: a) declaration before loop: double intermediateResult; for(int i=0; i < 1000; i++){ intermediateResult = i; System.out.println(intermediateResult); } b) declaration (repeatedly) inside loop: for(int i=0; … Read more
Given the following code interface IPerson { firstName: string; lastName: string; } var persons: { [id: string]: IPerson; } = { “p1”: { firstName: “F1”, lastName: “L1” }, “p2”: { firstName: “F2″ } }; Why isn’t the initialization rejected? After all, the second object does not have the “lastName” property. 6 Answers 6
What is Double Brace initialization syntax ({{ … }}) in Java? 13 Answers 13
Is it possible to create an empty array without specifying the size? For example, I created: String[] a = new String[5]; Can we create the above string array without the size? 14 Answers 14
Which method of checking if a variable has been initialized is better/correct? (Assuming the variable could hold anything (string, int, object, function, etc.)) if (elem) { // or !elem or if (typeof elem !== ‘undefined’) { or if (elem != null) { 31 Answers 31
I am initializing an array like this: public class Array { int data[] = new int[10]; /** Creates a new instance of Array */ public Array() { data[10] = {10,20,30,40,50,60,71,80,90,91}; } } NetBeans points to an error at this line: data[10] = {10,20,30,40,50,60,71,80,90,91}; How can I solve the problem? 10 Answers 10 data[10] = {10,20,30,40,50,60,71,80,90,91}; … Read more
MyClass a1 {a}; // clearer and less error-prone than the other three MyClass a2 = {a}; MyClass a3 = a; MyClass a4(a); Why? 5 s 5
I want to initialize a struct element, split in declaration and initialization. This is what I have: typedef struct MY_TYPE { bool flag; short int value; double stuff; } MY_TYPE; void function(void) { MY_TYPE a; … a = { true, 15, 0.123 } } Is this the way to declare and initialize a local variable … Read more
What is the best way to initialize a private, static data member in C++? I tried this in my header file, but it gives me weird linker errors: class foo { private: static int i; }; int foo::i = 0; I’m guessing this is because I can’t initialize a private member from outside the class. … Read more
I can create an array and initialize it like this: int a[] = {10, 20, 30}; How do I create a std::vector and initialize it similarly elegant? The best way I know is: std::vector<int> ints; ints.push_back(10); ints.push_back(20); ints.push_back(30); Is there a better way? 29 s 29 If your compiler supports C++11, you can simply do: … Read more
