Posts by Maniero • 444,682 points
6,921 posts
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viewsA: What’s the fastest way?
Hard to sink without knowing more information, but it is highly likely that keep in memory will always be faster under normal conditions. Access to an external device has always been much slower,…
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answers85
viewsA: Segmentation Fault with malloc()
Use the calloc() and be happy. scanf("%ld %ld", &n1, &n2); int *vetor = calloc(n2 - n1 + 1, sizeof(long int)); I put in the Github for future reference. When accessing the vector elements do…
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answer428
viewsA: Read a number starting with 0
If you want to ignore zero you must read decimally, and this is used %d, and for being a long long to be %lld: #include <stdio.h> int main(void) { long long valid; scanf("%lld", &valid);…
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answers6965
viewsA: Typed and untyped programming languages
Typing In essence all programming languages are typed, that is, all data is typed, and concretely the computer needs to have a type, even if it is unique. Dynamic X static Strictly speaking, there…
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answers169
viewsA: When should I worry about UX?
"Always", from the most basic to the most sophisticated software, unless you have zero user interaction even indirectly, which I’ve never seen. Of course in some cases you need less worry, in most…
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answers505
viewsA: Change the vector size during the course of the program?
Thus: int vetor2[4] = {1, 2, 4, 5}; I put in the Github for future reference. I know, you’re going to say you didn’t change the size, but you did create a new one, but that’s what you want to do…
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answers1445
viewsA: UPSERT or UPDATE-INSERT?
What do you call the second block of code in the question? I call it a command. It could be indented to make it clearer that it’s one thing. You mean you don’t have a password UPSERT? Okay, that’s…
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answers487
viewsA: Can we create artificial intelligence in any language?
Can be created in any language? Programming language? Yes, you can. If not, you cannot. Deep AI is an algorithm, with a lot of statistics and a lot of data and in one way or another they can do it.…
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answer1694
viewsA: Torque calculator in C
My question is how does the compiler know I’m working in binary? Is there any method that can put the number so the compiler knows that it really is a binary number? The compiler does not know, even…
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answers2944
viewsA: While use within the if
I imagine this is what you want: #include <stdio.h> int main(void) { int media = 0; while (media != -1) { printf("Digite a media do final aluno: \n"); scanf("%d", &media); if (media <…
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viewsA: What is an upsert?
What an upsert is? It is a command that inserts a new data if there is no one with the same primary key or updates if the key is found, so it never misses because there is no key as in UPDATE or…
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answer75
viewsA: What is the difference between "string_view" and "string" and which one should prefer?
To string_view is a simple reference to a string. The latter has an object with the data which is a string of characters. The former has a pointer to the string and how many characters are your…
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answer248
viewsA: Size of a very large Xamarin Forms application
Yes, totally normal, it is even small because it used techniques to remove much of the not so necessary excess. He needs to send all the necessary Mono, all the Xamarin, all the Xamarin Forms in…
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answer424
viewsA: What is the difference between using normal methods and Action or Func?
By default use methods, it has the smallest indirect possible. If it’s a simple static or instance method, there’s only the minimum necessary indirect that is to send to the part of the code where…
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answers2051
viewsA: Dropping indexes or Foreign Keys in a table can slow the query?
First let’s separate things. Creating index and placing a foreign key constraint are different things and not directly related. It is true even that this can cause a query to become slow? Failing to…
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answers218
viewsA: Public field X property
In case I assign the methods get/set, and to stay in the pattern I change the initial letter to uppercase, getting: string Nome { get; set; }; Now I can easily access the name variable through the…
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answer552
viewsA: Error: The object reference was not defined as an instance of a C#object
In the line before the error is transforming into string empty if what you find nay is null, which makes no sense. It makes sense to make that transformation if it is null. Changing this solves the…
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answers122
viewsA: What is it for { } inside the main
Actually, he’s got nothing, he’s just like the one you’ve always used. It only demarcates the beginning and end of a code instruction blocks that should be considered in a unique way for some…
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answer94
viewsA: Method that works without I call you directly
First you need to understand what is a framework. You are inheriting from DbContext that the Entity Framework knows what it is and knows there is a method OnModelCreating(). Somewhere within the…
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answer759
viewsA: What is a recursive method?
In C we have functions and not methods. Variables are not recursive, because to have recursion needs an action and variable is state. In general it can be used in place of a repeat loop. Most of the…
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answer255
viewsA: Allocation of operation in C
You don’t need the cast, but you need to use a number indicating that you are a float somehow. Both the 8, as to the 2 as to the 3 are integer numbers, so when he does the calculations they will…
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answers78
viewsA: In Java would a variable receive a function like in Javascript?
In Java 8 you can use the syntax of lambda. Before that only by creating functors, which is not exactly the same thing, but gives similar result. BiFunction<Integer, Integer, Integer> x = (a,…
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answer205
viewsA: What is the size limit of Indexeddb technology?
There is a differentiated limit between browsers? This is implementation detail and changes in each browser, where it’s running and even at the time. Don’t work with it. Today it is common to limit…
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answers162
viewsA: Syntax error in Mysql
Parentheses missing from line PRIMARY KEY: CREATE TABLE países ( cod_país INT NOT NULL AUTO_INCREMENT, nome_país VARCHAR(30), PRIMARY KEY (cod_país) ); Behold working in the Sqlfiddle. I also put in…
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answer113
viewsA: How to set a pointer as the default parameter in C++?
The first obvious problem is use float for monetary value, may not. But by a tremendous misfortune does not generate error, only causes problems sometimes, and the programmer thinks it is right.…
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answers353
viewsA: Why does Typescript when compiled convert "Let" to "var" in variables?
I can not answer in a specific authoritative way, but by what I know of compilation and transpilation, makes some sense because the extra control that the let gives is the scope, that the compiler…
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answers77
viewsA: How to modify the content of a root using a pointer?
The fact of being a root is orthogonal, that is, it does not matter for the question. Of course, doing it there is unnecessary, but I understand you want to do it just to exercise. Whenever…
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answers64
viewsA: Is expression-bodied recommended? Is there a performance difference?
It was created, so it’s recommended. In general there are no contraindications in the use that it was designed, which is something that just has a simple expression and already returns it. I would…
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answer43
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viewsA: Code::Blocks does not print pointer value
Do not use conio.h, even if you don’t have to. And if you have a bad compiler IDE (Dev-C++), stop doing this. Alias Code::Blocks does nothing in executing the same code, understand who’s who in…
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answer142
viewsA: Sort in C++ does not show the correct input value
There is an important semantic difference between the [2] using in two different places. Syntax is something that can be repeated with different meaning. It’s like a "take it to me" and "this is…
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answers3921
viewsA: puts() and printf(), when and which to use?
The basic difference is that the printf() has formatting and has a wider control of how to print the desired data, is a complete printing solution. The puts() is a very simple solution to play…
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answers187
viewsA: Ruby syntax
The object vet can call a method called each, it works very similar to for and could be replaced by him. This syntax refers to the object-oriented paradigm in which the object serves as the basis…
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answers140
viewsA: Substring program
The C also has and more efficient than was used, so I always talk to use what is ready, but be that :) Java does not have this inefficiency, but there is another. Not that it’s a problem for an…
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answers271
viewsA: Dapper requires writing SQL code, why?
Because Dapper was created like this, the technologies have their own characteristics, either to meet a demand that requires it to be so, either by the will of those who created it, or by…
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answers320
viewsA: Why can’t f-strings be used as docstring?
The mechanism of docstring It should be very simple, only to have a constant value that is stored somewhere and that if invoked it is brought up because who needed it. It was not the intention of…
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answer1373
viewsA: What is Feature Driven Development (FDD)?
It is one of many development models created in recent decades to make the software development process better. None of them has clear evidence of effectiveness and none is much different from using…
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answers106
viewsA: Function with a pointer?
When you are going to learn a new concept first study a lot what it is before and start doing, so you can understand what is happening and enjoy much more. Just making it work is not exactly what I…
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answer145
viewsA: Switch entering wrong case
The problem with this code is the lack of break in each case of switch, since this construction can all be executed, understand it as um goto` and not a decision mechanism, it jumps to the first…
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answer163
viewsA: How to use Emscripten?
The question is a little broad, I will answer what gives. I wanted to convert my codes into C++ for Javascript so I could use them in Web pages. It’s not that simple. While it is possible to do…
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answer323
viewsA: How to copy an array of struct to an equal one?
Since you are using code that you should only use in C and not in C++, you could use a C function: memcpy(e1, e2, sizeof(events) * 100); Documentation. Or you could use a C function++:…
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answers522
viewsA: Infinite loop on switch
The switch doesn’t work that way I I already answered about the problem. The break does not work as breaking the loop when it is inside the case, cannot use it. More about: Break and Continue on…
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answers930
viewsA: Prototype functions in C/C++
That is to say pointer to function, then in this way, just as a parameter can receive a reference to an object, the parameter can receive a reference to a function. So C has what’s called high-order…
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answers522
viewsA: Dynamic allocation of vectors
One of the reasons for the confusion is that code uses variable names that are difficult to understand what they mean. With better names one can follow better what is happening. The code does more…
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answers7494
viewsA: Handling of malloc() and realloc()
The exact answer to this depends on the implementation detail of the memory management functions, but I would say that in most cases it does in the same. Some people just use realloc() using a null…
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answer114
viewsA: Is that piece of code redundant?
Yes, it seems redundant, it is changing a data that is not used later in an object that will soon be destroyed. Taking advantage could have declared dado direct in its use and would have a less…
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answer75
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viewsA: How to give 'value' to a char variable?
Well, put "maria" in a variable like char it is not possible because this type waits only one character, it is possible to do this in a pointer to a properly allocated area in memory, which can be…
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viewsA: Why does this code give Segmentation fault?
You are not allocating each row, you are allocating the general and then a single row, to allocate each row would have to each of them within the loop of rows. I do not know if it gives the expected…
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answer1426
viewsA: What is the . isidentifier() method used in Python?
These methods are parsers of a text, it scans the entire text and analyzes whether all characters, without exception, fit certain rules, ie if all are within a character range that are valid for a…