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45
votes6
answers109646
viewsWhat does the error "Script execution disabled on this system" mean?
I was testing some things from PowerShell ISE so you can build some scripts. I realized that while I was running the script without saving the file, the commands were executed normally. However,…
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45
votes2
answers4966
viewsHow does an artificial neural network work?
I know that this question is quite commonplace and it is easy to find the answer, however, I would like a functional answer, I have seen enough about, but nothing enters my puppy, I’d like something…
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45
votes4
answers26195
viewsWhat is a payload?
I’ve always seen in some frameworks that work with REST or with sending data in JSON format in a request using the expression payload. What does that name mean in HTTP requests? What is specifically…
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45
votes3
answers3408
viewsHow to find out if a hexadecimal color is dark or light?
I have a status listing that is displayed and each status has an assigned color. These colors are saved in my database in hexadecimal format. Example: #add555 I have a small problem: If the color is…
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45
votes3
answers4342
viewsWhat is the difference between encryption, encryption and hash calculation?
I see a lot of confusion on the site about the terms. In the context of security of data what would be encoding, Encrypting and hashing and in which contexts each should be used? In particular, does…
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45
votes5
answers56754
viewsWhat is the difference between syntactic error and semantic error?
The concepts of syntactic and semantic error are found in books and other programming materials. However, always generate doubts for those who are starting. In a practical way. What is the…
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45
votes6
answers2425
viewsArrays are pointers, right?
After all, in C, an array a[] becomes a pointer *a? If not, what are arrays? What are the differences between them? How arrays work internally?
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45
votes6
answers10103
viewsWhat is a Web Service?
Lately I’ve heard a lot about Web Service. Web service is a solution used in systems integration and communication between different applications. Allow applications to send and receive data in XML…
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votes2
answers19996
viewsHow is the timestamp calculated?
The timestamp is the numerical representation of a date and is widely used in programming languages and in databases. I want to know: How is this calculation made? Is there any standardization for…
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votes3
answers10406
viewsHow does HTTPS (SSL) work?
Cryptography is something fundamental in web, because it provides us with privacy and security. It’s even possible that this is standard at HTTP 2. My question is: How does encryption via HTTP work?…
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votes7
answers2227
viewsAgile methodologies - a single programmer
I have heard a lot about agile methodologies and I really liked the idea. Of course, from what I saw, the client needs to cooperate, but it seems to me that for own projects (that is, whose idea is…
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45
votes5
answers41645
viewsWhat are the advantages and disadvantages between Mysql and Postgresql?
I have been with this doubt for a long time, I see some people recommending the use of Postgresql, but it is not clear the advantages and disadvantages compared to Mysql. I want to define the bank…
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45
votes5
answers76380
viewsHow to pin a "horizontal menu" to the top of the window when scrolling the page?
I have a layout with a horizontal navigation bar at the top of the site, it is with margin-top:100px, when scrolling the page the menu should be fixed at the top of the window but with margin-top:0.…
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44
votes2
answers2825
viewsWhat is a Turing stop problem?
I’ve read and reread on Wikipedia, I’ve watched some 15 videos in English and Portuguese on this subject, I’ve read several articles on google, but I can’t understand. Why would she go into an…
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44
votes4
answers3861
viewsWhat are the risks of using permission 777?
Always when I have folder permissions problem on my Ubuntu operating system, I usually give permission 777 for a particular folder. I usually do this in the development environment. In some…
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44
votes5
answers7270
viewsWhat is the difference between a "branch" and a "tag"?
In Git, what is the difference between a branch and a tag?
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44
votes3
answers12262
viewsWhat is the difference between architecture and software engineering?
Architecture of software Engineering of software Apparently these two concepts are related, but what is the difference between them?
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44
votes2
answers21131
viewsWhat does branch, tag and trunk mean?
What they mean and what best practices to use them?
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44
votes5
answers87966
viewsHow to print content inside a HTML div?
I have a page and in it the content I want to print. I created a Javascript command, but this command prints the whole page. Is there any way to print only the contents of a div?…
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43
votes1
answer2413
viewsWhat’s the difference between scope and lifespan?
What is scope? What is life time? They get confused? Visibility has something to do with this too?
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43
votes3
answers9745
viewsWhat are Javascript Promises (promises)?
I was researching about callback in Javascript when I found this question: How to really learn to use Promises (promises) in javascript? But after all : What are promises? What are they for?…
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votes4
answers31911
viewsWhat is the difference between compiled language for interpreted language?
What difference from compiled language to interpreted language, and what advantages to one another?
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votes1
answer2932
viewsIs using PDO the safest way to connect to a PHP BD?
I’m a beginner in PHP and would like to know if PDO(PHP Data Objects) is the safest way to connect to a database? I also need an example of how to make this connection and enter/select data.
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answer21497
viewsWhat is Reactive Programming (Reactive Programming)?
Can someone explain to me clearly and objectively? I read some more articles still not very clear.
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votes4
answers53481
viewsHow to decrypt MD5?
If I have the following code $senha = md5("senha") and send it to the database $senha, it should be possible to recover this MD5 at the bank and show "password" back on an information update form,…
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43
votes3
answers1083
viewsTo what extent is premature optimization a problem?
Premature optimization is when there is an excessive concern on the part of the programmer with the performance of the application. It is usually condemned by some programmers for reasons such as:…
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43
votes4
answers67145
viewsComposition and aggregation: what are the differences and how to use them?
Object orientation is common for objects of a certain class to have references to one or more objects of other classes. A very simple example is an object of a class Pedido with reference to a list…
oopasked 10 years, 4 months ago SomeDeveloper 18,074 -
43
votes3
answers8167
viewsWhen to use recursion and when to use loops?
A problem can be solved and get the same result used a loop or through recursive calls to a function. Whereas the programming language being used has both features, how to know when one is better…
function loop software-engineering encoding-style recursionasked 10 years, 5 months ago Maniero 444,682 -
43
votes5
answers2270
viewsUsing unused affect performance?
While I was developing, I saw that in most of my classes contained a certain amount of using that were not being used and came to me the doubt of the title. Using unused affects the performance of…
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43
votes5
answers22471
viewsHow do anonymous functions work?
I know they are functions that do not have the specified name, but what is the purpose? Is it possible to recur with anonymous functions? Ex: Fibonacci sequence. (function(x, y) { alert(x + y);…
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43
votes2
answers6588
viewsHow can I pause and play a gif?
I want to put on my site, a system like 9gag, where people can pause and give play in a .gif. I know I have to use two images, one .jpg and a .gif, but tried some functions and could not. I found…
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votes4
answers1480
viewsWhat is the correct way to simulate a <script> with a new language?
Suppose I implemented a new language and I have a functional interpreter written in javascript. Something like mylang.interpret(code_as_string). Now I would like to create an interface in which I…
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43
votes7
answers3681
viewsWhat are the implications of not declaring variables in PHP?
In php I can do this without declaring/defining variables: echo($foo); //resolve: vazio, sem nada $foo++; echo($foo); // resolve: 1 Using var_dump() the same gives, respectively NULL and 1. If I use…
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42
votes5
answers2375
viewsShould I show generic error messages like, wrong password or user, or specific messages?
It is common in many systems when entering the user and the incorrect password, the system informs us that one of them is wrong, but not exactly what (it happens also here in Stack Overflow). Does…
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42
votes5
answers43935
viewsWhat is a Table Test? How to apply it?
It is quite common to read while studying algorithms and programming logic that the Table Test is a means of verifying the functioning of an algorithm. What is the Table Test? How is it possible to…
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42
votes6
answers3282
viewsIs there a Javascript class?
I am studying Javascript and saw some explanations that left me with doubts. Here at Stackoverflow I saw several questions about the possibility of creating an abstract class in Javascript. But my…
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42
votes3
answers5198
viewsDifference between the use of typeof and is
In C# when I need to check if a variable is of a certain type, I usually use the operator is: if(qualquerVariavel is int) Console.Write("A variável é int"); I know it is also possible to check the…
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42
votes2
answers5738
viewsWhat is PHP Injection? How does it differ from SQL Injection? And how do you avoid it?
What is PHP Injection? What difference does it make to SQL Injection? How to avoid PHP Injection in my application? What are the main forms of PHP Injection type attack? Updating Observing:…
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42
votes2
answers1922
viewsWhy do they say that recursive setTimeout is better than setInterval?
I see online a series of articles with titles like: setInterval is bad, which translating would be setInterval is ruin. I saw recommendations to use an anonymous recursive function with a…
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42
votes14
answers126839
viewsPhone Mask Using jQuery Mask Plugin
I need to change the "-" position on the mask. <label for="telefone" >Telefone</label> <input style="width:25%; margin-right:25% " type="tel" name="telefone" id="telefone"…
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42
votes3
answers105525
viewsHow do I get the project back to a specific commit?
Assuming a condition where, I have a project with 20 commits, and I decide for inexplicable reasons to go back some independent commits if I want to go back 4, 5 or 10, assuming the description of…
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42
votes4
answers6910
viewsHow does namespaces work in C#?
I’m studying C# and I came across namespaces. How it works and when it’s applied? If possible some basic example.
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42
votes1
answer27667
viewsWhy and when to use Enum in Java?
Someone who is learning the language, novice or experienced, may never have crossed paths with Java enumerations. I have read several times that they are useful, for example, to implement the…
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42
votes3
answers6498
viewsHow to model a tree data structure using a relational database?
How to appropriately and efficiently define naturally organized tree-based data in relational databases, considering the physical implications of this? That is, organize in a way that minimizes the…
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42
votes4
answers18382
viewsWhat is the difference between null and Undefined?
Most programming languages have a "null" type to represent the absence of a value. It can have multiple names (null, nil, None, etc), but its purpose is the same (with the exception of SQL, where…
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42
votes3
answers3888
viewsWhy is using global variables not good practice?
I’m reading a Javascript book called "Javascript The Good Parts" and in it at various times the author says that one should not use global variables because they are of "evil". Why are they…
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41
votes2
answers1150
viewsHow to count the objects present in the image with PHP?
The original photo of the bean is this: It lowers the resolution of the photo, I’ve already applied a grey-scale filter and increased the contrast to maximum to turn black and white. Then I examined…
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41
votes1
answer2950
viewsWhat is an indirect?
I read in some places about programming that something does or should do an indirect. What is this and what it’s for?
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41
votes8
answers3166
viewsFewer moves from a horse to a given house in Chess
On a chessboard in any house I have a Horse (represented in red) and I will have only one other piece (represented in green) that the horse must go to it: I must use the simplest path and take into…
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41
votes2
answers21537
viewsOauth - What is it? What is its purpose?
What is Oauth? What is its purpose? What does he do? There are other alternative technologies to it?