void | 易学教程

Returning from a void function [closed]

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问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed last year . Which is more correct way to return from function: void function() { // blah some code } OR void function() { // blah some code return; } Rationale for second way: It expresses developer intentions more clearly. It helps detecting function end at pre-compile time: Suppose you

Understanding the difference between f() and f(void) in C and C++ once and for all

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问题 Ok, so I have heard different opinions on this subject and just want to make sure I understand it correctly. For C++ Declarations void f(); and void f(void); mean precisely the same thing, the function f does not take any parameters. Ditto for definitions. For C Declaration void f(void); means that f does not take any parameters. Declaration void f(); means that function f may or may not have parameters, and if it does, we don't know what kind of parameters those are, or how many there is of

async Task vs async void

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问题 This might be a very stupid question, but I have the following lines of coding that convert RAW images to BitmapImages: public async void CreateImageThumbnails(string imagePath, int imgId) { await Task.Run(() => controlCollection.Where(x => x.ImageId == imgId).FirstOrDefault().ImageSource = ThumbnailCreator.CreateThumbnail(imagePath)); } which calls this method CreateThumbnail() public static BitmapImage CreateThumbnail(string imagePath) { var bitmap = new BitmapImage(); using (var stream =

Uses for the Java Void Reference Type?

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There is a Java Void -- uppercase V-- reference type . The only situation I have ever seen it used is to parameterize Callable s final Callable<Void> callable = new Callable<Void>() { public Void call() { foobar(); return null; } }; Are there any other uses for the Java Void reference type? Can it ever be assigned anything other than null ? If yes, do you have examples? Tom Hawtin - tackline Void has become convention for a generic argument that you are not interested in. There is no reason why you should use any other non-instantiable type, such as System . It is also often used in for

How to test void method with Junit testing tools?

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I just happen to implement a method void followlink(obj page,obj link) which simply adds page and link to queue. I have unsuccessfully tried to test this kind of method. All I want is to test that in the queue contains page and link received from followlink method. My test class already extends TestCase. So what is the best way to test such a method? The JUnit FAQ has a section on testing methods that return void . In your case, you want to test a side effect of the method called. The example given in the FAQ tests that the size of a Collection changes after an item is added. @Test public void

What is System.Void?

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问题 I know that methods declared with void does not return anything. But it seems that in C# void is more then just a keyword, but a real type. void is an alias for System.Void like int that is for System.Int32 . Why am I not allowed to use that type? It does not make any sense, but this are just some thoughts about the logic. Neither var nothing = new System.Void(); (which says i should use void (Not an alias?)) nor var nothing = new void(); compiles. It is also not possible to use something

Can someone explain a void return type in Java?

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问题 The only void return type I have seen has System.out.println statements in a method. So once the method is called those Strings will be printed. Couldn\'t you make the return type string and have the string returned instead of doing void return type? If the void return type method has other methods in it could you make the return type the value which the method gives which would return the outcome of that method? When is it that you could only use the void return type? 回答1: Can someone

What's the better (cleaner) way to ignore output in PowerShell? [closed]

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Let's say you have a method or a cmdlet that returns something, but you don't want to use it and you don't want to output it. I found these two ways: Add-Item > $null [void]Add-Item Add-Item | Out-Null What do you use? Which is the better/cleaner approach? Why? I just did some tests of the four options that I know about. Measure-Command {$(1..1000) | Out-Null} TotalMilliseconds : 76.211 Measure-Command {[Void]$(1..1000)} TotalMilliseconds : 0.217 Measure-Command {$(1..1000) > $null} TotalMilliseconds : 0.2478 Measure-Command {$null = $(1..1000)} TotalMilliseconds : 0.2122 ## Control, times

What does `public static void main args` mean?

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问题 I am not sure what this means, whenever before you write a code, people say this public static void main(String[] args) { What does that mean? 回答1: Here is a little bit detailed explanation on why main method is declared as public static void main(String[] args) Main method is the entry point of a Java program for the Java Virtual Machine(JVM). Let's say we have a class called Sample class Sample { static void fun() { System.out.println("Hello"); } } class Test { public static void main

in c: func(void) vs. func() [duplicate]

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问题 This question already has answers here : Is it better to use C void arguments “void foo(void)” or not “void foo()”? [duplicate] (6 answers) Closed 2 years ago . When a C function does not accept any arguments, does it have to be declared/defined with a \"void\" parameter by the language rules? PC-Lint seems to have problems when there\'s nothing at all in the argument-list, and I was wondering if it\'s something in the language syntax that I don\'t know about. Edit: I just found a duplicate