default-value

Default value of boolean and Boolean in Java

由 人走茶凉 提交于 2019-11-26 06:19:12
问题 What are the default values of boolean (primitive) and Boolean (primitive wrapper) in Java? 回答1: The default value for a Boolean (object) is null . The default value for a boolean (primitive) is false . 回答2: The default value of any Object , such as Boolean , is null . The default value for a boolean is false. Note: Every primitive has a wrapper class. Every wrapper uses a reference which has a default of null . Primitives have different default values: boolean -> false byte, char, short, int

How would I skip optional arguments in a function call?

由 喜欢而已 提交于 2019-11-26 05:17:27
OK I totally forgot how to skip arguments in PHP. Lets say I have: function getData($name, $limit = '50', $page = '1') { ... } How would I call this function so that the middle parameter takes the default value (ie. '50')? getData('some name', '', '23'); Would the above be correct? I can't seem to get this to work. Your post is correct. Unfortunately, if you need to use an optional parameter at the very end of the parameter list, you have to specify everything up until that last parameter. Generally if you want to mix-and-match, you give them default values of '' or null , and don't use them

Default Values and Initialization in Java

由 自作多情 提交于 2019-11-26 03:48:50
问题 Based on my reference, primitive types have default values and Objects are null. I tested a piece of code. public class Main { public static void main(String[] args) { int a; System.out.println(a); } } The line System.out.println(a); will be an error pointing at the variable a that says variable a might not have been initialized whereas in the given reference, integer will have 0 as a default value. However, with the given code below, it will actually print 0 . public class Main { static int

Entity Framework 6 Code first Default value

由 心不动则不痛 提交于 2019-11-26 03:21:18
is there "elegant" way to give specific property a default value ? Maybe by DataAnnotations, something like : [DefaultValue("true")] public bool Active { get; set; } Thank you. You can do it by manually edit code first migration: public override void Up() { AddColumn("dbo.Events", "Active", c => c.Boolean(nullable: false, defaultValue: true)); } ravinsp It's been a while, but leaving a note for others. I achieved what is needed with an attribute and I decorated my model class fields with that attribute as I want. [SqlDefaultValue(DefaultValue = "getutcdate()")] public DateTime CreatedDateUtc {

Initialization of a normal array with one default value [duplicate]

由 微笑、不失礼 提交于 2019-11-26 03:15:02
问题 This question already has answers here : How to initialize all members of an array to the same value? (22 answers) Closed 2 years ago . C++ Notes: Array Initialization has a nice list over initialization of arrays. I have a int array[100] = {-1}; expecting it to be full with -1\'s but its not, only first value is and the rest are 0\'s mixed with random values. The code int array[100] = {0}; works just fine and sets each element to 0. What am I missing here.. Can\'t one initialize it if the

How to populate/instantiate a C# array with a single value?

由 可紊 提交于 2019-11-26 02:52:14
问题 I know that instantiated arrays of value types in C# are automatically populated with the default value of the type (e.g. false for bool, 0 for int, etc.). Is there a way to auto-populate an array with a seed value that\'s not the default? Either on creation or a built-in method afterwards (like Java\'s Arrays.fill())? Say I wanted an boolean array that was true by default, instead of false. Is there a built-in way to do this, or do you just have to iterate through the array with a for loop?

Change default text in input type=“file”?

由 橙三吉。 提交于 2019-11-26 02:51:47
问题 I want to change default text on button that is \" Choose File \" when we use input=\"file\" . How can I do this? Also as you can see in image button is on left side of text. How can I put it on right side of text? 回答1: Each browser has it's own rendition of the control and as such you can't change either the text or the orientation of the control. There are some "kind of" hacks you may want to try if you want an html/css solution rather than a Flash or silverlightsolution. http://www

How to set a default value for an existing column

由 為{幸葍}努か 提交于 2019-11-26 02:49:35
问题 This isn\'t working in SQL Server 2008: ALTER TABLE Employee ALTER COLUMN CityBorn SET DEFAULT \'SANDNES\' The error is: Incorrect syntax near the keyword \'SET\'. What am I doing wrong? 回答1: This will work in SQL Server: ALTER TABLE Employee ADD CONSTRAINT DF_SomeName DEFAULT N'SANDNES' FOR CityBorn; 回答2: ALTER TABLE Employee ADD DEFAULT 'SANDNES' FOR CityBorn 回答3: cannot use alter column for that, use add instead ALTER TABLE Employee ADD DEFAULT('SANDNES') FOR CityBorn 回答4: The correct way

How would I skip optional arguments in a function call?

由 孤者浪人 提交于 2019-11-26 02:13:56
问题 OK I totally forgot how to skip arguments in PHP. Lets say I have: function getData($name, $limit = \'50\', $page = \'1\') { ... } How would I call this function so that the middle parameter takes the default value (ie. \'50\')? getData(\'some name\', \'\', \'23\'); Would the above be correct? I can\'t seem to get this to work. 回答1: Your post is correct. Unfortunately, if you need to use an optional parameter at the very end of the parameter list, you have to specify everything up until that

Default value to a parameter while passing by reference in C++

由 北慕城南 提交于 2019-11-26 02:08:25
问题 Is it possible to give a default value to a parameter of a function while we are passing the parameter by reference. in C++ For example, when I try to declare a function like: virtual const ULONG Write(ULONG &State = 0, bool sequence = true); When I do this it gives an error: error C2440: \'default argument\' : cannot convert from \'const int\' to \'unsigned long &\' A reference that is not to \'const\' cannot be bound to a non-lvalue 回答1: You can do it for a const reference, but not for a
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