Questions tagged [constructors]
Member functions of a class which initializes objects of the given class.
153 questions
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Primary constructors for depedency injection
Microsoft identifies dependency injection as one of the uses for primary constructors.
public class ExampleController(IService service) : ControllerBase
{
[HttpGet]
public ActionResult<...
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How do you handle instantiating a large number of interconnected component objects?
I'm currently refactoring our instance startup code, which is currently a 2,000 line mud method. The issue is that that method needs to create a large number (>50) of components/service objects, ...
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Assigning to fields in function or by function?
While writing the constructor for class A in Python, I calculate some of the class's fields using function fun(). This function is never used outside the constructor of instances of this class.
In ...
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Why do we need factories in the first place?
I went through various blogs but nowhere I can find the reason of having virtual constructors in C++.
Why is virtual constructor needed and lets say if we go through the wrong way of creating virtual ...
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How to efficiently build objects without default constructors
I am trying to explain and understand a way to create object which cannot have "default" instances. Typically I want classes which represent, as closely as possible, the real-life concept I ...
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How are parameters values passed into a MVC controller constructor?
For this MS sample code, I have checked Program.cs, Startup.cs, and other config files, don't see how the two parameters sqlQueryService and sqlCommandService are populated. Appreciate if someone can ...
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How to signal a dealbreaker error from a c-tor?
Context: 128kB RAM, freeRTOS.
Considered solutions:
Exceptions. Discouraged by both the memory size and the code style guide.
Late bool init(...);. Has worked for a decade but has it's problems - can ...
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Smart pointer class choice: Simplicity vs. right tool for the job
I'm wrestling with a design choice question here.
I've got a class that needs a couple of semaphores. Semaphores are non-movable objects. Objects of this class however need to go into a vector (there'...
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Do db calls in constructors lead to more DRY code?
It recently came to my attention that its best practice to avoid database calls in constructors. I feel like this means you end up repeating unnecessary code, thus the code is less DRY?
For example, ...
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Constructor initializer list too bloated?
I noticed that my Member initializer list is not really readable.
My main.cpp files looks like this:
#include "Application.hpp"
using Pathfinding::Core::Application;
int main()
{
...
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Conversion methods: from_xxx() or to_xxx(), is there a reason I shouldn't stick with to_xxx()?
I have a C++ library that I'm converting to Python. In the C++ library I have multiple constructors and many different types of conversion functions (think radians to degrees, and different types of ...
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Why aren't constructors atomic? [closed]
If thrown exceptions in constructors can lead to memory leaks or partially-constructed objects, then why we don't make them atomic? so neither an object nor it's local variables will get created/...
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Can and should constructors do more work than merely assigning values to fields? [duplicate]
A typical introductory example to OOP, classes, and constructors is object Car, with properties such as float fuel, bool is_engine_running, etc etc, and a class and constructor definition might be as ...
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Is a "wrong" to return anything else besides `this` in a constructor?
Is a "wrong" to return anything else besides this in a constructor?
Take this TypeScript Queue sample:
class Queue {
private buffer: string;
constructor(buffer: string = "&...
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When and how to check input parameters
My SmsRecipientDetails class constructor accepts String value as recipient phone number.
I would like to accept number with spaces:
assertDoesNotThrow(() -> new SmsRecipientDetails("123456789 &...
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