constants

问题 What is the value of HSHELL_FLASH 回答1: Assuming you meant the actual integer value, HSHELL_FLASH is defined in WinUser.h as #define HSHELL_FLASH (HSHELL_REDRAW | HSHELL_HIGHBIT) where #define HSHELL_REDRAW 6 #define HSHELL_HIGHBIT 0x8000 thus the actual value is 0x8006 . 回答2: The value is 42. Just kidding. By "value" I'm assuming you're looking for a basic explanation of what this variable represents. HSHELL_FLASH is a handle to a window that needs to be flashed. HSHELL_FLASH should be

问题 What is the best way to define a double constant in a namespace? For example // constant.h namespace constant { static const double PI = 3.1415926535; } // No need in constant.cpp Is this the best way? 回答1: I'd say: -- In c++14: namespace constant { template <typename T = double> constexpr T PI = T(3.1415926535897932385); } -- In c++11: namespace constant { constexpr double PI = 3.1415926535897932385; } -- In c++03 : namespace constant { static const double PI = 3.1415926535897932385; } Note

问题 Can you define a constant using the const keyword in C. I am finding conflicting information. Used the #define macro and hard code the value to test. The code will compile in those cases but is throwing an error when I use the const keyword. int main(void){ const int TESTARRAYSIZE = 7; float user_array[TESTARRAYSIZE] = {5.1, 7.2, 5.1, 8.45, 23.0, 67.123, 5.1}; float number_in_question = 5.1; float frequency; frequency = user_array[1]; printf("%.2f", frequency); return(0); } compile error:

问题 I have constants, that are made of other, smaller constants. For example object MyConstants { final val TABLENAME = "table_name"; final val FIELDNAME = "field_name"; final val INDEXNAME = TABLENAME + "_" + FIELDNAME + "_ix"; // this one does not want to be constant } I want these to be true constants because I use them in annotations. How do I make it work? (on scala 2.11) What I want is interface MyConstants { String TABLENAME = "table_name"; String FIELDNAME = "field_name"; String INDEXNAME

问题 In Swift REPL I can assign a constant with let , but why can I modify it later using var ? let name = "al" var name = "bob" Swift is not complaining here, but wasn't name a constant? 回答1: Redeclaring a variable (in the same scope) is not valid in Swift: $ cat test.swift let name = "al" var name = "bob" $ swiftc test.swift test.swift:2:5: error: invalid redeclaration of 'name' var name = "bob" ^ test.swift:1:5: note: 'name' previously declared here let name = "al" ^ However, the Swift REPL

问题 I'm in the process of evaluating the benefits of Zend_Config_Ini versus using a simple constant file. e.g. - define('DB_HOST',localhost); //versus $config = new Zend_Config_Ini('/path/to/config.ini', 'staging'); echo $config->database->params->host; // prints "dev.example.com" The only thing is that the $config is not globally accessible. So then you need to use Zend_Registry to store for application usage, without having to initiate each time. This seems to add more complexity than needed...

问题 I understood what a compile time constant rule is from Compile-time constants and variables. declared as final have a primitive or String type initialized at the same time as the declaration initialized with constant expression final int x = 5; But I fail to understand why below code doesn't: final int x; x = 5; The only difference is of third point above. How initialization on different line instead of same line makes a difference. 回答1: Case 1 final int x = 5; public static void main(String[

问题 I understood what a compile time constant rule is from Compile-time constants and variables. declared as final have a primitive or String type initialized at the same time as the declaration initialized with constant expression final int x = 5; But I fail to understand why below code doesn't: final int x; x = 5; The only difference is of third point above. How initialization on different line instead of same line makes a difference. 回答1: Case 1 final int x = 5; public static void main(String[

问题 From past Year are so, we have developed an application, in which we have used the static String Constants to store the Constants. Like public static final String PAYMENT_CHEQUE = "cheque"; Where Ever I Require i.e. in the jsp pages as well the Action class I will be refering to the Above String Constant I am thinking after reviewing the Resource Bundle, properties Files, My Question is Is there any performance hit if I use the properties file compared to Static String Constant? Which is

问题 As per the title. I have the following code which creates a binary search tree, but if I want it created and changed dynamically with user input, how would I do that if I can't change the value of a variable in haskell?!? find :: (Ord a) => Node a -> a -> Bool find (Node val left right) s | s == val = True | s < val = find left s | s > val = find right s find Empty s = False data Node a = Node a (Node a) (Node a) | Empty myTree = Node "m" (Node "a" Empty Empty) (Node "z" Empty Empty) Thanks