logo
Tags down

shadow

Why do I need to provide constructor implementation in header? C++


By : Rezam Alkhaldi
Date : July 31 2020, 03:00 PM
Does that help You declared 2 classes with same name, your cpp is completely wrong. It does not contain implementation of constructor declared in hpp file, it declares another class and it's implementation. main.cpp includes hpp file and look for implementation which does not exists.
So at first never use reserved keywords as names! test.hpp:
code :
#pragma once
#include <string>
class Test{
public:
    std::string name;
    Test(std::string name);
};
#include "test.hpp"

Test::Test(std::string name)
{
    this->name = name;
}


Share : facebook icon twitter icon

Constructor in implementation versus header


By : user3757828
Date : March 29 2020, 07:55 AM
Hope that helps The constructor should, to my knowledge, be defined in the implementation file but I've only been able to find examples with the class inside one main file instead of split into a .h and .cpp file
code :
cEntity::cEntity (int x, int y, int height, int width) {
   X,Y,Height,Width = new int;
   X = new int(x);
   Y = new int(y);
   Height = new int(height);
   Width = new int(width);
cEntity::cEntity (int x, int y, int height, int width) {
    :X(new int(x))
    ,Y(new int(y))
    ,Height(new int(height))
    ,Width(new int(width))
{}

Does an available compiler provide an implementation of the C11 '_Atomic' keyword and its related header 'stdatomic.h'?


By : Mikołaj Trawiński
Date : March 29 2020, 07:55 AM

Is it okay to provide the definition of a constructor inside the header file that declares it?


By : Janysson Silva
Date : March 29 2020, 07:55 AM
With these it helps Yes, you can define constructors in the header file, typically inside the class definition itself as you have been doing.
No, it isn't necessarily poor practice. For example, it is probably silly to create a cpp file just to put the constructor definition somewhere other than the header, if the constructor is short and simple.

Can I provide an incomplete header for a C++ class to hide the implementation details?


By : user3234729
Date : March 29 2020, 07:55 AM
it should still fix some issue The short answer is "No!"
The reason: any/all 'client' projects that need to use your Class class have to have the full declaration of that class, in order that the compiler can properly determine such things as offsets for member variables.
code :
// impl.h
struct MyInternal; // An 'opaque' structure - the definition is For Your Eyes Only
class Class {
public:
    Class();
    init();
    doSomething();
private:
    MyInternal* hidden; // CLient never needs to access this! Compiler error if attempted.
}

// impl.cpp
#include <api.h>
#include <impl.h>

struct MyInternal {
    SomeLibrary::Type myData;
};

Class::Class() {
    init();
}
Class::init() {
    hidden = new MyInternal; // MUCH BETTER TO USE unique_ptr, or some other STL.
    hidden->myData = SomeLibrary::Type(42);
}
Class::doSomething() {
    hidden->myData.doSomething();
}

Getting 'Context is not constructible. Add a default constructor or provide an implementation of IDbContextFactory."


By : Nicholas Phillips
Date : March 29 2020, 07:55 AM
Any of those help Essentially you need a default ctor (that's the error) - but just implementing it would lead to problems.
You'd have to implement the IDbContextFactory for the results to be consistent (or your migration from code won't work etc.).
Related Posts Related Posts :
  • Access properties of a virtual class in partial class
  • Does calling multiple times save() method of hibernate with same object insert new record in DB?
  • how to give multiple runtime permissions in android Q programmatically
  • Rules for top-level function definitions order in Racket and Common Lisp
  • API to insert data to array of objects in mongoDB
  • String parsing in ruby
  • How to close this modal
  • Validate a input dict schema
  • Allow user to copy text from a password field
  • is there something wrong with this JavaScript if statement?
  • How to perform edit action in ASP.net Core?
  • Filtering on Keys inside an array of objects
  • Docker installation on Windows 10 Home
  • How to modify a list value in a nested custom datatype?
  • How to post a message to google chat room using C#? (**Error**: Request had insufficient authentication scopes)
  • Difference between Account-level and User-Level Network Policies
  • Single Number solving by Haspmap, return always be a "@"
  • How to get all USA timezone IDs using nodatime
  • How to check if a user is already created, if not, create, else show an error message that a user is created Laravel
  • create strings using combinations of list items
  • Concat values in postgresql without null values
  • multiple usage of ggplot
  • Create a loop to label dates base on month without the use of many multiple 'case', 'between'
  • Change color of leaflet map
  • Polymer/Lit-element, child component doesn't re-render when the property is modified by the parent
  • Why is static_cast used in QT's official document
  • How to pass object of unknown type to function
  • Size of picture in background repeat?
  • Angular 8 - How to handle error response?
  • store strings in stable memory in c++
  • how to convert HAC flexible query to DAO query
  • Cannot refresh UI if update in ItemView
  • iterator .end() from std::list returns "0xcdcdcdcdcdcdcdcd" but .begin() as expected
  • How to make a function to use dict keys as variables to a class?
  • Using disabledDate in Antd Datepicker in table
  • Best approach to remove cassandra-topology.properties file in running cluster nodes
  • Replace values in XML file with values of a vector
  • Convert old SQL Database in compatibility mode
  • plsql store procedure loop compare value
  • Sum same property object by group
  • Is std::sqrt the same as sqrt in C++
  • What do you do about the JLabel classes? It says, "JLabel not a statement" for the error
  • How to add a CSS to this JavaScript or HTML on click buttons?
  • Iterate through std::initializer_list
  • Functional Interface call for a new Instance
  • Is it OK to inherit an empty Interface?
  • Why does the overidden run method in java.lang.Thread produce a bizarre output?
  • Typescript: type one parameter based on the other
  • changing background image of div using javascript
  • Microsoft Bot Framework: Smilies in MS Teams
  • Codeblocks c++ code doesn't run in VS 19 (vector subscript out of range)
  • How to convert two arrays of strings to the array of objects like key and value with particular keys in javascript?
  • What is the fastest way to find if a column has at least one NULL value in ORACLE database?
  • Rename headers - 'list' object is not callable
  • Authorize with both ASP.NET core MVC/Razor site AND a WebAPI
  • When I tried to add ArrayList into ArrayList second ArrayList is repeating
  • If I implement IEquatable<T>, will I lose the option to compare by reference?
  • Is it possible to pass data from an angular7 component or service to index.html file?
  • Passing res.send value from node.js backend to react.js
  • Vim shortcuts to select and copy the current line without the next line
  • shadow
    Privacy Policy - Terms - Contact Us © voile276.org