initialization

问题 How would I turn this: xmlObject *system_domain = [xmlObject alloc] xmlObject *system_description = [xmlObject alloc] xmlObject *system_type = [xmlObject alloc] Into something where I would only have to write xmlObject and [xmlObject alloc] once. xmlObject *system_domain, *system_description, *system_type = [xmlObject alloc] This makes all of them xmlObjects, but does not allocate each one. Any help would be much appreciated. 回答1: If you've got a set of related objects, and being able to

问题 class Actor { let agent: String? = "nobody" init(agent: String){ self.agent = agent // error: immutable value 'self.agent' may only be initialized once } } let John = Actor(agent: "xyz") I'm confused about the sequence that is happening here (I'm fully aware of the differences between var and let ). But why do I get that error? If I'm using the init method, then doesn't that mean I'm not using the default parameter? Why can't I change the default constant with another one? 回答1: You cannot

问题 class Actor { let agent: String? = "nobody" init(agent: String){ self.agent = agent // error: immutable value 'self.agent' may only be initialized once } } let John = Actor(agent: "xyz") I'm confused about the sequence that is happening here (I'm fully aware of the differences between var and let ). But why do I get that error? If I'm using the init method, then doesn't that mean I'm not using the default parameter? Why can't I change the default constant with another one? 回答1: You cannot

问题 I'm implementing a simple application in Java. I'm using the MVC module for the app. The problem is that when my Controller creates the objects of the View and the Model , when trying to use a simple get method I get the defaults values and not the new ones, that I inserted in the UI. Here is a code exmaple: View: public class Client extends JFrame { private float ammount; private JButton calculateButton; ... public void startUI(ActionListener listener) { EventQueue.invokeLater(new Runnable()

问题 I'm implementing a simple application in Java. I'm using the MVC module for the app. The problem is that when my Controller creates the objects of the View and the Model , when trying to use a simple get method I get the defaults values and not the new ones, that I inserted in the UI. Here is a code exmaple: View: public class Client extends JFrame { private float ammount; private JButton calculateButton; ... public void startUI(ActionListener listener) { EventQueue.invokeLater(new Runnable()

问题 What's the best way to avoid (or control) the initialisation by the designer of a heavy custom property in .NET? Sometimes it is important to have a property set to something initially without that setting being acted upon when initially set. In the imaginary example below, I want to achieve the flexibility of having something like UpdateSetting as a property, but not the inconvenience of having the database set to zero every time the application starts up. All I can think of is another

问题 Similar to This SO Post and This SO Post I initialize a variable ----> idHERE: static func createPractitionerRole(fromRoleDict roleDict:[String: AnyObject])->PractitionerRole?{ guard let (nameL, idL) = getRoleNameId(fromRoleDict:roleDict) else { return nil } let roleTypeL = ProTouchRoleType.determineRoleTypeFromProTouchId(idL) var idHERE = Identifier(withValue: idL, systemParam:Constants.CodeSystem.ProTouch.coding_system_proTouchURL) print("idHERE \(String(describing: idHERE))") print("idHERE

问题 `new function()` with lower case "f" in JavaScript My intuition says using the new keyword would be slower. Is there any noticeable benefit to using either method? 回答1: My guess would be that the function constructor form ( new function() { } ) would be faster than returning an object literal in a closure ( (function(){ return {}; })() ) because the latter seems to be doing a little more work than the former. However, it appears I am wrong, at least for a couple modern JavaScript engines.

问题 I wrote some code in my project, and I found that I should put my buttonlistener in the public void initialize() , or I can't use the button. I don't know what the initialize() mean in javafx , why I can't change it to another method name? This is initialize method in my code, I don't implement Initializable. So what't the mean of this in javafx? public void initialize() { weight_number1.setOnAction(e -> number(1)); weight_number2.setOnAction(e -> number(2)); weight_number3.setOnAction(e ->

问题 So I have tried looking up a few things that seemed helpful, but ultimately were not. I am supposed to initialize a 6x8 matrix as a 2D array in a separate function. I have three files, a main function file, a functions file, and a header file. Here is relevant code from main int plate[MAX_ROWS][MAX_COLS]; double A = 0, B = 0, T1 =0, T2 = 0, C = 0; printf("\n"); printf("Welcome to the Heat Plate Simulation\n\n"); printf("Enter: Heat-A, Heat-B, Plate-1, Plate-2, Stab-Crit\n\n"); scanf("%lf%lf