Questions tagged [constants]

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Term for a map of constants [closed]

Considering there's a map of string constants, most commonly with a key and a value being equal, e.g. in TypeScript: const itemTypes = { FOO_BAR: 'FOO_BAR', BAZ_QUX: 'BAZ_QUX', } as const; They ...
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Define "constants" at the global or function scope?

I often define variables that will never change, i.e. constants, at the top of a script/module. But recently I've been wondering if it makes sense to define them at the function scope level if they ...
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140 votes
3 answers
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Where do "magic" hashing constants like 0x9e3779b9 and 0x9e3779b1 come from?

In code dealing with hash tables, I often find the constant 0x9e3779b9 or sometimes 0x9e3779b1. For example hash = n * 0x9e3779b1 >>> 24 Why is this particular value used?
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Visibility of constants

Should constants of my class only be public if I know that they will be used from their users or doesn't it hurt to make all of my constants public per se? Is not exposing all constants cleaner?
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Should I use accessors or public static fields for global constants?

I have to work on some code that was CAST-audited. The report says that it is bad in Java to use public static and that accessors should be preferred. That is also what I was taught at school. The ...
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4 answers
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Is a constant name related to its current value an anti-pattern? [closed]

For example, suppose I have a string constant like this: const TITLEBAR_MESSAGE="Welcome back, %USERNAME%!"; I think it is more readable when it is named as const WELCOME_BACK_USERNAME="Welcome ...
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2 answers
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Referencing Database Primary Keys from Codebase

I don't have a lot of experience with these kind of issues, but I feel I need to consult on this issue. The current codebase I'm working on is using what I consider to be a questionable technique to ...
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5 answers
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I feel like these constants should be in a different class?

I have a static class called RenderingUtilities that houses several useful methods and constants. Some of these constants are related to the Earth as an object such as the Earth's radius. I believe ...
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Should I replace a constant with static methods, if that constant usually 'cooperate' with a specific operator?

For example, to convert between g and kg, I have a constant 1000: public static final float G_TO_KG=1000; . . . this.result = someResult*1000; I found G_TO_KG always bind to operator '*'. So my ...
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2 votes
3 answers
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When defining constants, which is more important? Easier to find? Or narrower scope?

For example, consider I have constants VOL_MIN and VOL_MAX, which is used inside 1 function only: public void setVolume(int val){ final int VOL_MIN = 1; final int VOL_MAX = 10; val=Math....
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Should I make constant for values of three choices (trivalent/ternary)?

For two choices there is boolean. In my case, I have positive, negative, and neutral which are three choices and cannot be represented by boolean. I've see there's method Math.signum(x) in Java which ...
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Is it a good practice to store constants in configuration files [duplicate]

In my project I have some constants where I reference almost everywhere: public sealed class Constants{ public static readonly int MAX_QUAL { get; } = 1080; public static readonly bool CC { ...
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3 votes
1 answer
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Should I avoid creating a variable with shorter name for a constant?

suppose I have code like this someFunction:function(userId){ var url=SomeClass.SomeNetworkConnector.SOME_URL; if(url !== undefined && userId !== undefined){ this.openURL(url+"?userid="...
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28 votes
7 answers
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May a value of a constant be changed over time?

During development phase, there are certain variables which need to be the fixed in the same run, but may need be modified over time. For example a boolean to signal debug mode, so we do things in the ...
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Should I rename variables that are already constants in my own library?

I'm writing a high level wrapper around the Python socket.socket object. Specifically, I want to do this for IPv4 TCP sockets (though it would be useful to be able to expand the library later with ...
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Is it bad practice to define constants using class static methods?

Instead of using #define or const, I usually define constants using class static methods as follows: //AppConstants.h #include <string> class AppConstants{ public: static int getMax(); ...
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Should I use one class for one constant?

Originally, in most languages, I would like to put constants into a class like that: public class AppConstants{ public static final double HEIGHT_MAX=20.0; public static final int COUNT_MAX=...
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49 votes
7 answers
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Is it a bad practice to have an interface to define constants?

I am writing a set of junit test classes in Java. There are several constants, for example strings that I will need in different test classes. I am thinking about an interface that defines them and ...
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