The non-static block: { // Do Something… } Gets called every time an instance of the class is constructed. The static block only gets called once, when the class itself is initialized, no matter how many objects of that type you create. Example: public class Test { static{ System.out.println(“Static”); } { System.out.println(“Non-static block”); } public … Read more
Arrays.asList can help here: new ArrayList<Integer>(Arrays.asList(1,2,3,5,8,13,21));
Using the syntax that you used, int array[100] = {-1}; says “set the first element to -1 and the rest to 0” since all omitted elements are set to 0. In C++, to set them all to -1, you can use something like std::fill_n (from <algorithm>): std::fill_n(array, 100, -1); In portable C, you have to … Read more
$myArray = []; Creates empty array. You can push values onto the array later, like so: $myArray[] = “tree”; $myArray[] = “house”; $myArray[] = “dog”; At this point, $myArray contains “tree”, “house” and “dog”. Each of the above commands appends to the array, preserving the items that were already there. Having come from other languages, … Read more
Which is better, a or b? From a performance perspective, you’d have to measure it. (And in my opinion, if you can measure a difference, the compiler isn’t very good). From a maintenance perspective, b is better. Declare and initialize variables in the same place, in the narrowest scope possible. Don’t leave a gaping hole … Read more
If you want to make it clear what each initializer value is, just split it up on multiple lines, with a comment on each: address temp_addres = { 0, // street_no nullptr, // street_name “Hamilton”, // city “Ontario”, // prov nullptr, // postal_code };
Edit: This has since been fixed in the latest TS versions. Quoting @Simon_Weaver’s comment on the OP’s post: Note: this has since been fixed (not sure which exact TS version). I get these errors in VS, as you would expect: Index signatures are incompatible. Type ‘{ firstName: string; }’ is not assignable to type ‘IPerson’. … Read more
Double brace initialisation creates an anonymous class derived from the specified class (the outer braces), and provides an initialiser block within that class (the inner braces). e.g. new ArrayList<Integer>() {{ add(1); add(2); }}; Note that an effect of using this double brace initialisation is that you’re creating anonymous inner classes. The created class has an … Read more
If you are going to use a collection that you don’t know the size of in advance, there are better options than arrays. Use a List<string> instead – it will allow you to add as many items as you need and if you need to return an array, call ToArray() on the variable. var listOfStrings … Read more
You want the typeof operator. Specifically: if (typeof variable !== ‘undefined’) { // the variable is defined }