230 questions
3
votes
2
answers
106
views
Disambiguating ambiguous function overloads because of converting constructor
Given a wrapper type
template <typename T>
struct Ptr
{
Ptr(T*);
};
a class hierarchy
struct Base {};
struct Derived : Base {};
and a set of function overloads
void f(Ptr<Base>);
...
- 101
1
vote
1
answer
98
views
How to check what constructor overload is used
If I have a class constructor with two overloads taking in different inputs, is there a way to tell them apart? For example,
class example
{
double ExampleDouble;
char ExampleChar;
public:
...
- 19
0
votes
0
answers
63
views
Should a constructor with a std::initializer_list be explicit?
I am designing a container (yeah, do not reinvent the wheel, I know). Let's call it Container<T>.
I have a constructor to allow the initial number of elements:
explicit Container(std::size_t ...
- 999
1
vote
0
answers
51
views
CS0121 Ambiguous Call with Collection Initializer [duplicate]
I'm on a team with two other devs. For the past few months I've been working on a project in C# 12 independently, and only recently have the other devs pulled my code and run it. For one of them it ...
- 73
1
vote
0
answers
183
views
How can I overload a constructor in a private nested class without getting a "Resource Not Found" error when I call Inherited Create?
I have a Managed Record named TEmail with a nested private class called TEmailForm that inherits from TForm. The idea is my email Record can create a modal form as needed for the user to type an email....
- 9,514
0
votes
2
answers
56
views
How can I call constructor with less parameters with no assignment of default value to a class variable in Java?
public class Sample {
int id;
String name;
int age;
Sample(int i, String n){
id = i;
name = n;
}
Sample(int i, String n, int a){
id = i;
...
- 1
1
vote
1
answer
99
views
Deduce member size from initialization list in constructor (CWG 1591) What's the right way? [duplicate]
I have a class Vec<C> that works as below, and I need to know a way to write the constructor and/or deduction guide such that a braced-enclosed initializer list deduces C as std::array<T,N>...
- 394
2
votes
3
answers
164
views
Two identical constructors however compiler selects the templated one
I am trying to implement a list container in C++, and I have problem with compiler selecting the wrong constructor overload.
The constructors are as follows:
list(size_type count, const T& value);
...
- 61
3
votes
1
answer
169
views
Inheriting constructors and forwarding reference
Consider the following two classes:
struct Base {
Base() = default;
Base(auto&&);
};
struct Derived : Base {
using Base::Base;
};
If I try the following test with Type = Base and ...
- 3,335
0
votes
1
answer
55
views
Overloaded function not outputting correct answer
I am attempting to create an overloaded contructor that will take in integer and add them with the byteAdd function. However; whenever I compile the output is always the default constructor rather ...
1
vote
2
answers
169
views
How to make compiler differentiate f(double...) and f(int, double...)
I am writing a small library for working with polynomials.
The main class is called poly and it contains 4 overloaded constructors.
An object of class poly is a representation of one polynomial.
Full ...
3
votes
2
answers
964
views
OOP Python Overloading the '__init__' method
I am porting a project from Java to Python and there is a class with multiple constructors. I'm trying to port that same idea to python, in a pythonic way. I've recently been informed of the typing....
- 136
0
votes
0
answers
31
views
how can i limit the user to a certain input [duplicate]
Hi I'm trying to learn java
This a simple program that stores a patient's blood details, well in any case how can i keep the program accurate by means of returning an error message if the input was ...
- 1
1
vote
2
answers
761
views
Class constructor overloading in Typescript
I am working on a class PlaybackControl, I use it to create two HTMLElements:
PlaybackControlButton: HTMLButtonElement
PlaybackControlMenu: HTMLDivElement
Now, to initialise the class object, I need ...
- 416
1
vote
1
answer
1k
views
Can I overload init from C++ side in pybind11?
If in C++ a class had an overloaded constructor:
class MyClass {
std::string name;
public:
MyClass(){};
MyClass(std::string name_){ name = name_;}
};
how do I expose this to python? Can I ...
- 3,203
1
vote
1
answer
55
views
abstract constructors or equivalent in kotlin
I have some code for a abstract Binary Tree class with nodes. I have an add(value : N) method and and add(value : E)that just takes an element and automatically creates the Node.
As you can see below ...
0
votes
0
answers
32
views
Python: Change behaviour of [] list instatiation/comprehension [duplicate]
I am working on a solo project and I find myself using very often the following:
list_obj = list(map(func, list_obj))
I want to just add the map functionality to the list class to avoid bloat and ...
- 135
-1
votes
1
answer
95
views
Do I need to overload the constructor | factory method for each combination of constructor's | factory method's arguments?
I have 4 instance variables that can be initialized by default, is the code written below appropriate? The number of constructors is growing a terrible pace, will I use the Builder object that have ...
- 85
0
votes
1
answer
849
views
Default constructor with all parameters given default values?
I was reading the book by Joyce Farell on C++, and it's saying that a default constructor is the one with no arguments. I understood it without any hiccups. But things started getting worse after it ...
0
votes
1
answer
276
views
Constructor parameter with byte, short and int throwing error
I am trying to implement constructor overloading by using byte, short and long together. I am passing three values from main method and want to check which constructor gets called Test(byte, short, ...
- 21
1
vote
2
answers
562
views
Constructor parameter with int and long or double and float throwing error
I am trying to implement constructor overloading by using int and long together and double and float together. I am passing two int values from main method and want to check which constructor gets ...
- 21
3
votes
2
answers
218
views
F# Add multiple constructor overloads that call the base class constructor
I'm trying to create a dictionary with structural equality in F# and I want to pass through several dictionary constructor overloads.
In C# this would look like
class StructuralDictionary<Key, ...
- 3,415
2
votes
2
answers
227
views
Error: A delegating constructor cannot have other mem-initializers
I have the class as follows:
class A{
private:
int a;
int b;
int c;
public:
A(int a1){
a1 >= 0 ? a = a1 : a = -1;
}
A(int a1, int b1, int c1) : A{ a1 }, b{ b1 }, c{ ...
user21380625
4
votes
0
answers
47
views
Inside of `__new__`, why is `cls` required instead of `args[0]`? [duplicate]
I have two almost identical implementations of the __new__ method for a class.
However, in one case, there is an error message.
In the other case, it works fine.
class Klass1():
# causes ...
- 4,700
2
votes
1
answer
2k
views
ShortCut for showing all the constructor overloads in Visual Studio 2022
What is the way to show all the overloads of a constructor in C++ in Visual Studio 2022?
Suppose I have a Rectangle class, and I have 3 overloads for them. When I hover my mouse in any of them, ...
- 333
-2
votes
2
answers
89
views
Using two constructors on one object
I have a User class that has two constructors. When I create an object and use the two constructors, one of them gives me an error saying: no match for call to '(User) (double&, double&, ...
2
votes
2
answers
158
views
How do we call Base class Constructor from Derived Class using delegating Constructors
I know and I have read many threads to call a base class constructor from a Derived class, But I wanted to implement it using Delegating constructors
Here is my code
The error states
"A ...
4
votes
4
answers
118
views
How to call the base constructor of an object from overloaded varargs constructor?
I have a simple class with a constructor of all available fields and i want to add an overloaded constructor with varargs to allow the creating of objects even if some fields are unknown.
class ...
- 749
1
vote
1
answer
79
views
Why is the universal T&& constructor called when another constructor is more specific?
In the following snippet I have reconstructed a small failing example of what I'm working on right now. The class entity should be able to gobble up different "functor" types, hence it has ...
- 5,374
1
vote
1
answer
146
views
Typescript arrow functions overloads error 2322
This code below is working fine, but it gives an error for the resolve constant.
const resolve: Resolve
Type '(param: "case 1" | "case 2" | "case 3") => boolean | &...
- 753
0
votes
2
answers
382
views
why we can't use multiple this() in Constructor Overloading?
i'm newbie in this world currently i'm learning java and i wanna to know why i can't use multiple this() in a constructor someone can tell me why please?
public class Student {
private String ...
-2
votes
1
answer
676
views
Why does pybind fail for functions without arguments?
I have an overloaded constructor in C++ (default + other). My automatically generated pybind code looks like this:
py::class_<MyClass>(m, "MyClass")
.def(
py::...
- 63
1
vote
1
answer
91
views
Which Constructor takes precedence when there are two matches for a Generic Class's Constructor
What determines which constructor is used if a Generic class has 2 constructors:
One takes (T data), and another (string errorMessage).
And an instance is created with type string?
For me it seems to ...
- 126
0
votes
0
answers
44
views
New to C++ constructors : why is the output of this program 1 2 and not 1 0 2 0 [duplicate]
why is the constructor Number() not being invoked when a number data type is initialized without any values ?
#include <iostream>
using namespace std;
class Number {
int n;
public:
...
2
votes
1
answer
251
views
initializer_list constructor somehow excluded from std::variant constructor overload set
Help me solve this puzzle: In the following code I have an std::variant which forward declares a struct proxy which derives from this variant. This struct is only used because recursive using ...
- 5,374
1
vote
1
answer
340
views
C++ using placement new causes segmentation fault in constructor
please find below code. In this code, when I use "placement new", the I see segmentation fault in constructor, I am not sure why it is causing this, since I can create normal objects. Also, ...
- 843
0
votes
3
answers
173
views
Is it possible to have constructor with the same number of variables and data type? [duplicate]
I just want to know if we can use overloading constructor with the same number of variables, same data types with the different variables.
Employee(String firstName, String lastName, String jobRole){
...
0
votes
2
answers
5k
views
Python function overloading recommended approach
Assume a function that takes an object as parameter. There could be various ways to express the parameter object creation, some of which expressive, and likely easier to be used.
To give a simple ...
- 143
0
votes
2
answers
85
views
object constructed as one base class, method calculated as other base class (diamond inheritance and code redundancy)
I have a diamond inheritance scheme in C++ solved through virtual inheritance.
The base class is general has two attributes and some method using them.
class general {
double attr1, attr2;
public:
...
- 129
1
vote
1
answer
227
views
Deduction guide based on number of parameters passed to constructor
Here's something I'm trying that doesn't seem to work: I want to toggle a compile time switch based on how a class object is instantiated. If there's just one constructor argument, the LengthOpt ...
- 5,374
1
vote
1
answer
494
views
Constructor Chaining with subclasses in Java
Just a question RE: Constructor Chaining in subclasses that I can't find a good answer on and I'm confusing myself a bit with.
I'm making a basic little Text Based RPG for some practice and I'm going ...
- 100
0
votes
0
answers
26
views
Overload Resolution with Deleted Constructor C++ [duplicate]
I'm sure this question exists elsewhere, but can't find an answer. I've noticed that when a constructor is defined as deleted, it makes that type take part in overload resolution. In other words, if ...
- 525
-1
votes
1
answer
51
views
Python programming to remove certain characters from certain positions in a string
Question:
s=
"campaign_5Nu_E_0_87872_shard1.zip"
desired output:
campaign5Nu_E_0_87872shard1.zip
Guys help me........
0
votes
1
answer
75
views
How do I make sure all these constructors are called?
This is about c# constructors and has been asked before a couple of times. However, the questions and answers never really fit my scenario:
public abstract class BaseClass {
public List<int>...
- 1,487
0
votes
2
answers
305
views
Copy Constructor vs Assignment Operator Overload in the dynamic array class in C++
We made a dynamic array class during lecture and the instructor copy-pasted the copy_constructor code on the assignment_operator_overload.
But don't we need to delete the existing dynamic array first ...
- 1
0
votes
1
answer
712
views
Generic constructor template called instead of copy/move constructor
I've designed a simpler wrapper class that adds a label to an object, with the intent of being implicitly convertible/able to replace the wrapped object.
#include <string>
#include <...
- 1,767
1
vote
1
answer
82
views
How to provoke a compile-time error if a specific overload of a function is called?
According to https://en.cppreference.com/w/cpp/string/basic_string_view/basic_string_view, std::basic_string_view class has 7 overloaded ctors. I only care about 2 of them since right now I don't use ...
- 3,735
1
vote
2
answers
498
views
C++ N-API Multiple Type Signatures
I am learning C++ and playing around with OpenCV and node-addon-api. I wanted to create my own wrapper for cv::Vec. docs
#include <napi.h>
#include <opencv2/core/matx.hpp>
class Vec : ...
- 5,273
21
votes
1
answer
1k
views
Why doesn't std::string have a constructor that directly takes std::string_view?
To allow std::string construction from std::string_viewthere is a template constructor
template<class T>
explicit basic_string(const T& t, const Allocator& alloc = Allocator());
which ...
- 918
0
votes
4
answers
457
views
How to use if else statement in java constructor
I am trying to overload a constructor in java. There are two Strings among its variables which is problematic if I write two separate constructors in the case of only one of these strings being called....
user13911186