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Questions tagged [declarations]

15 questions
20
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3 answers

Is it good to define a variable inside a loop?

My instructor once told me that I should not define a variable inside a loop, but I honestly still do not understand why. What are the disadvantages of that? Could any body explain that to me?
Mo Haidar
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20
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4 answers

Why do we have to mention the data type of the variable in C

Usually in C, we have to tell the computer the type of data in variable declaration. E.g. in the following program, I want to print the sum of two floating point numbers X and Y. #include main() { float X=5.2; float Y=5.1; float Z; …
user106313
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5 answers

Why is *declaration* of data and functions necessary in C language, when the definition is written at the end of the source code?

Consider the following "C" code: #include main() { printf("func:%d",Func_i()); } Func_i() { int i=3; return i; } Func_i() is defined at the end of the source code and no declaration is provide before its use in main(). At the…
user106313
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10
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9 answers

What is the possible disadvantage of putting declarations in inner blocks, instead of at beginning of function?

At the place where I work, there are explicit guidelines for placement of declarations of variables. According to that, it is required to put them at the global level and / or at the beginning of functions, and not in inner blocks (such as a for…
TCSGrad
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7
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4 answers

C# declaration redundancy

When declaring a member class MyClass { AnyClass> myProp = new AnyClass>(); } is quite redundant. We may find the following, more concise, less…
Joseph Merdrignac
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7
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4 answers

Reason behind multi-line declaration style?

I'm a little curious about the reason behind the Windows header file declaration styles. When I read them, I see multi-line declarations such as the following: WINBASEAPI HANDLE WINAPI GetStdHandle( IN DWORD nStdHandle ); What is the…
user541686
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3 answers

Declaring variables in Python and PHP

The question is how to cope with absence of variable declaration in Python, PHP, and the like. In most languages there is a way to let the compiler know whether I introduce a new variable or refer to an existing one: my in Perl (use strict) or…
Alexander Gelbukh
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2
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1 answer

How to compute whether it is guaranteed the variable is set?

Assuming declarations are expressions consider such code: if ((var x = foo()) and (var y = x)) or (var z = bar()) then println(z); end The reference to x is OK, because at this point x has to be set, but the reference to z (in println) is not. It…
greenoldman
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2
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Is there a difference between declaring variables outside or inside a loop?

Is there any difference if I were to write something like this: int row,col; for(row = 0; row < data.length; row++){ for(col = 0; col < data[row].length;col++){ //do something }//end for loop(columns) }//end for…
user3189506
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3 answers

Declaring a field name starting with underscore

Before forming a class in Java or other programming languages that support OOP, should I use underscore (_) in each (local or private) field declaration. More precisely: private String _customername; Is this a correct declaration?
Hakan
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Scheme's define in Common Lisp

In Common Lisp, we have to use the let form to declare a new lexically-scoped variable. This means that the code either looks like that written in C89 (all variables declared on top of scope), or acquires unreadably deep nesting. let* is somewhat…
ndsrib
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4 answers

Regarding a variable in C, is an assignment always equivalent to a definition of that variable?

Is there a difference between defining a variable in C and assigning a value to a variable in C? I know that declaring a variable simply means telling the name and its type like int a. On the other hand defining a variable means telling the compiler…
yoyo_fun
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3 answers

Understanding the concept of "arguments" and "parameters"

In the third last paragraph at page number 26 of the ebook "The C Programming Language" the author(s) say, "We will generally use parameter for a variable named in the parenthesized list in a function. The terms formal argument and actual argument…
user106313
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2 answers

Where are C variables declared

I see a lot of code with variables declared right after the function, but when I post something like that people end up mad and say it is better to declare them when they are used. I assume this all compiles to the same executable, so it is simply a…
floopdagoop
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Best way to handle variables used in a for loop?

From previous experience, I had always thought that, if you are going to use variables inside of a for loop, it was much better to declare them outside of the loop vs. inside the loop itself. I recently had a code review done and had several younger…
user25839
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