Declaration is the part of the subprogram (procedure or function) which provides the protocol(header), but not the body of the subprogram.
Questions tagged [declaration]
3407 questions
108
votes
5 answers
When to use an object instance variable versus passing an argument to the method
How do you decide between passing arguments to a method versus simply declaring them as object instance variables that are visible to all of the object's methods?
I prefer keeping instance variables in a list at the end of the Class, but this list…
Ziggy
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106
votes
8 answers
Declaring variables without var keyword
At w3schools there is written:
If you declare a variable, without using "var", the variable always becomes GLOBAL.
Is it useful to declare global variable inside the function? I can imagine to declare some global variables in some event handler,…
xralf
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103
votes
3 answers
How should I use the "my" keyword in Perl?
I keep seeing the my keyword in front of variable names in example Perl scripts online, but I have no idea what it means. I tried reading the manual pages and other sites online, but I'm having difficulty discerning what it is for, given the…
FistOfFury
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100
votes
1 answer
What's the purpose of this [1] at the end of struct declaration?
I was snooping through my MSP430 microcontroller's header files, and I ran into this in :
/* r3 does not have to be saved */
typedef struct
{
uint32_t __j_pc; /* return address */
uint32_t __j_sp; /* r1 stack pointer */
…
Alexander
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96
votes
8 answers
Semicolon after class declaration braces
In C++ classes, why the semi-colon after the closing brace? I regularly forget it and get compiler errors, and hence lost time. Seems somewhat superfluous to me, which is unlikely to be the case. Do people really do things like:
class…
SmacL
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90
votes
3 answers
Has the new C++11 member initialization feature at declaration made initialization lists obsolete?
With C++11, we now have the ability to initialize class members in a header declaration:
class aClass
{
private:
int mInt{100};
public:
aClass();
~aClass();
};
So I'm a bit confused. Traditionally initialization…
Vector
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89
votes
11 answers
Declaring an object before initializing it in c++
Is it possible to declare a variable in c++ without instantiating it? I want to do something like this:
Animal a;
if( happyDay() )
a( "puppies" ); //constructor call
else
a( "toads" );
Basially, I just want to declare a outside of the…
Quantum7
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88
votes
7 answers
Where you can and cannot declare new variables in C?
I heard (probably from a teacher) that one should declare all variables on top of the program/function, and that declaring new ones among the statements could cause problems.
But then I was reading K&R and I came across this sentence: "Declarations…
Daniel Scocco
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88
votes
3 answers
86
votes
2 answers
Can a JavaScript object property refer to another property of the same object?
I recently tried to create an object like this:
var carousel = {
$slider: $('#carousel1 .slider'),
panes: carousel.$slider.children().length
};
My intentions were to improve jQuery's selector performance by caching the results of…
Bungle
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84
votes
4 answers
Add keys/values to Dictionary at declaration
Very easy today, I think. In C#, its:
Dictionary dict = new Dictionary() { { "", "" } };
But in vb, the following doesn't work.
Public dict As Dictionary(Of String, String) = New Dictionary(Of String, String)…
XstreamINsanity
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81
votes
3 answers
I do not understand why this compiles
I'm certainly missing something, but I do not understand why this compiles (with both g++ & clang++):
struct A
{
};
struct B
{
};
int main()
{
A a(B);
}
First of all, B is a type... not a value. How should I interpret this code?
Picaud Vincent
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78
votes
7 answers
Where to declare/define class scope constants in C++?
I'm curious about the benefits/detriments of different constant declaration and definition options in C++. For the longest time, I've just been declaring them at the top of the header file before the class definition:
//.h
const int MyConst =…
bsruth
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75
votes
9 answers
Why is adding attributes to an already instantiated object allowed?
I am studying python, and although I think I get the whole concept and notion of Python, today I stumbled upon a piece of code that I did not fully understand:
Say I have a class that is supposed to define Circles but lacks a body:
class Circle():
…
NlightNFotis
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74
votes
8 answers
What’s the difference between “{}” and “[]” while declaring a JavaScript array?
What’s the difference between “{}” and “[]” while declaring a JavaScript array?
Normally I declare like
var a=[];
What is the meaning of declaring the array as var a={}
Venkat
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