Posts by Maniero • 444,682 points
6,921 posts
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viewsA: Why is the "private" access modifier letting me change the attribute outside the class?
It’s simple, the code mixes things that are different. You put one class inside the other, then it gets access. Only this is wrong, the classes must be separated according to what you want. What you…
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viewsA: What’s the Context class for?
The Entity Framework implements a project standard called Repository. It has a complex mechanism that controls data access and gives an appearance of simplicity to your code. He doesn’t have all the…
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answer416
viewsA: Relational model for user login
Without knowing the real requirements there is not much to help, they are always the ones who will define what is right or wrong. If there was only one way to do it then everything would be ready…
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viewsA: Are the variables of a function automatically deleted after its termination?
The question is a little confused because it speaks in method and uses an example that seems to be a function (it could be just an excerpt from a class). The local variables of a function or method…
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answers1800
viewsA: In which table is the foreign key in a ratio 1 to 1?
The question is good and made me think of something that we don’t always realize. We learn (I think) that N is the countermastery and that is where the foreign key is. I don’t have such a formal…
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answer241
viewsA: What is the advantage of using the latest version of . NET Framework?
It depends on what you call the advantage. But it has several fixes of bugs and some Features. Several features of C# 7 only work with this version (others are not working with it), such as tuples…
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answer2089
viewsA: ALTER TABLE changing column name
Actually to change only the correct name is : ALTER TABLE tabela RENAME COLUMN nome_antigo TO novo_nome; I put in the Github for future reference.…
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answers244
viewsQ: What is a heuristic?
Is it the same as artificial intelligence? What is the relationship between these things? Why does it matter to us programmers? Can you give an example to illustrate?
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answer88
viewsA: How to interrupt a cycle of "whiles"?
The code is not very clear what you want, but it would be more or less this: loop@ while (a > b){ // Meu while principal while (c > d) { while (e > f) { break@loop } } } I put in the Github…
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viewsA: Is it possible, in a function, to return the reference to an array index?
Yes, it is possible, you have to say in the name of the function that it is by reference, both in your statement and in the call: function &ref(&$list) { $return = &$list[3] ?? false;…
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answers299
viewsA: How to make Visual Studio interpret an hour that is larger than 23hrs and smaller than 6hrs at the same time?
First of all Visual Studio cannot do something like this because it is an IDE, it is a tool for writing code and it is not its function to calculate dates. But if you want to know how to program in…
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answer67
viewsA: What is the difference between Reduce and Foldl in Elixir?
Reduce uses the first element of the sequence as a starting point in what it will do. Fold has an initial value passed to begin with. So if you’re going to add all elements of a collection and you…
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answers1154
viewsA: What type of variable allocates less memory, integer or string?
What kind of fruit fits more units from inside a box of same size, grape or watermelon? Even if you know what it is, what’s the point if you like watermelon? You should use numeric types to…
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answer1738
viewsA: How to make an if with a higher and a lower value?
The first step is to define well what your problem is. Even in English it is not well defined. One thing is for, another is a if, another is a if and then else if, And even if this is less relevant,…
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answers2429
viewsA: What is the logic behind the "days * 24* 60* 60* 1000"?
It’s just a basic math, how many hours is a day? How many minutes is an hour? How many seconds is a minute? How many thousandths is a second? That’s all it is, finding the number of thousandths of a…
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viewsA: Is there anything equivalent to Mysql’s "FOR UPDATE" in Sqlite?
No, and there’s no point in it. Sqlite works with unique write transactions, so there can only be one write at a time and the entire database is locked for write operations on every write you want…
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answer60
viewsA: Why do you have to add -pthread option when compiling with the Std thread library?
Actually, there are other libraries that need this. The main libraries are together in a binary file that is always used when doing the linkediting. Libraries that are not within this binary need to…
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viewsA: What’s behind the "go"?
How does Python know that that character is called a letter? The line is saying. when I replaced the letter with for bola in frase: and the code continued to work And why would it be different? You…
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viewsA: Basic doubt about function diff Assoc - PHP
Because PHP is a language of weak typing and tries to interpret everything that gives as the same type, so 2 is the same as "2". If this bothers you look for a strong typing language. PHP rules are…
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answer718
viewsA: Difference between Ahead-Of-Time and Just-in-Time compilation
The AOT compiler is the most traditional where you develop, in it you invoke the compiler and it does the whole process culminating in the executable that can be called on time or transported to…
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answers4293
viewsA: Break and Continue on foreach Java 8
Well, for this example it doesn’t make much sense, but I will consider it to be used somewhere it does. And it depends on the concrete example to give a suitable solution. Anyway the forEach() It is…
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answer149
viewsA: What is concatenative programming language?
According to Wikipedia, Examples of concatenative languages are Cat, Enchilada, Factor, Onyx, Postscript, RPL, Staapl, Trith, XY, Kitten, Om, Min and Forth so none actually used by anyone today, and…
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answer450
viewsA: What is considered primitive in a programming language?
The term is not very well defined so it may be what someone says it is, so it may be other things, but we’re not going that far. On primitive types what is considered more is the type that has…
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viewsA: Do I need to re-allocate a structure in case I clean up just a part of it?
There are a lot of problems in this code and even in the question, but I will focus on what you asked. This free() does not do what you imagine. You can only give free() on something you’ve given…
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answer356
viewsQ: What would be a good hash calculation algorithm to use in a scattering table?
In the question Why String hashcode() in Java uses 31 as multiplier? There is talk of the use of the number 31 as a multiplier. There has been a controversy about the motivation of this number. In…
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viewsQ: What makes cache invalidation a difficult solution?
There’s a famous phrase: There are only two hard problems in Computer Science: cache invalidation and naming Things -- Phil Karlton So she says it’s hard to name things, which has a funny tone since…
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answer86
viewsA: Does not accept Enum parameter with non-zero integer
In fact you should not accept any number, after all an integer is a value of a type and you expect a value of an enumeration, which case has integers with subliminal values. Doubt remains because 0…
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answer204
viewsA: Type a word and return the word with uppercase vowels
This code does not make much sense, is all "run over". It starts with a problem that does not cause error. Why transform a string in string? Why separate the comma vowels if you only need to put the…
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answer1898
viewsA: Difference and use between Primary Key and Foreign Key
To primary key is the data you need to control the access to the tables' rows. It must be unique and therefore it cannot have null value (theoretically it could have a null key, but it doesn’t make…
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answer60
viewsA: Code pattern for function calling
Let’s define the terms well. Let’s call the function what is in the library or created by you. What is talking about in the question (if and foreach) are reserved keywords of the language. It is not…
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viewsA: "If <condition> Then" block makes no sense
This is the same in any language, it’s checking if 1 is equal to 2, which is obviously false and will If be false since the other conditions are linked by a And. So it was probably a way for the…
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answer170
viewsA: Calculations with String in Java
In the way you put it doesn’t make sense to do this, if you already have the numbers use them directly, in fact you don’t even need to do math. But considering they’re actually variables you have to…
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answer60
viewsA: In a chained list structure, why is a pointer to the node pointer used?
Lista is a type to organize the list, it is not the next structure, it is the first, it is where it starts the list. If every node is accessed via a pointer, how is the first node accessed? By an…
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answer174
viewsA: How does "array.Sort()" work?
Part has already been answered in What the operator means "=>"? (or all of these What is Arrow Function and when to use?). It makes sense. Whenever you use a function you should read its…
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viewsA: Is it possible to "force" Javascript typing?
Declaring types has nothing to do with language being strongly typed. In fact, it’s not even being statically typed, which I think is what I meant. You can read more about this at What is the…
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answer90
viewsA: Create recycle bin table
What’s best is you only know because only you are making the case. I don’t know if it’s because people don’t understand that, or if they’re really stubborn, or if they think that I and other people,…
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answer201
viewsA: Correct use of "goto" with "if Else"
Yes, there is, and much simpler: <?php $valor01 = 10; $valor02 = 8; if ($valor01 > $valor02) echo "valor01 é maior que valor02<br>"; else echo "valor02 é maior que valor01"; ?> Behold…
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answer140
viewsQ: What algorithm to use for a diff mechanism?
You know these mechanisms of Difference of content that we use in control of various versions, where can be seen on Wikipedia or on Github, even here on the site? Just as there are algorithms known…
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viewsA: Rounding down in Python
The contrary function of the ceil() (ceiling) is the function floor() (floor). See the documentation (it is on the same page of ceil(). from math import floor a = 5.92 b = floor(a) print(b) Behold…
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answer146
viewsQ: What is Tree Depth and height?
I asked the question What is Breadth First and Depth First?. Perhaps a slightly simpler subject matter would be what are the depth and height of a tree structure. And why this matters in the data…
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viewsA: Pointers per parameter in C++
On the line customers = new Cliente(); I put in the Github for future reference. you are changing the content of a local variable, when you finish running the function this variable ceases to exist…
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answer338
viewsA: What is Leaky abstraction (abstraction leak)?
As the definition already existing there, abstraction is to hide details, is to generalize a solution where the mechanism is more hidden and give only a point of contact and a contract of how to…
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viewsA: How to store various information in JS properly?
Usually we programmers group the members of the object into something unique and do not keep the members separate. Thus, the queue would be composed of various objects representing people. In the…
javascriptanswered Maniero 444,682