Upcasting permits an object of a subclass type to be treated as an object of any superclass type.
Questions tagged [upcasting]
244 questions
0
votes
2 answers
up-casting a function to another of base class parameter
I want to up-cast a function whose parameter is of type Sub to another function type whose parameter is of type Base. (Sub extends Base)
std::function child_f = ...
std::function base_f =…
One Two Three
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1 answer
Upcasting in C (learning class inheritance)
Thanks for taking a look at my post, hopefully it will be relatively simple.
I am attempting to learn more about QP/C or QP/nano, but as part of understanding how it works I need to learn about OOP concepts in C. Which is detailed…
DisplayName001
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c++ how to downcast from upcasted derived
I have a class named "package" which is the base of the derived "shader_package".
The package instances generally get exclusively generated in a function called load. It has a pointer to package as a return parameter. Therefore I can also return…
MoustacheSpy
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3 answers
Upcasting not to real base class
I'm a bit stuck with such awful problem of bad class hierarchy.
class A {...}; // abstract
class B : public A {...}; // abstract
class C {...}; // abstract
class a1 : public B, public C {...}; // indirect inheritance of A
class c1 : public A,…
Nikita Smirnov
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2 answers
Runtime upcasting failure from Thinking in Java
When running this code, why would it have runtime error?
The array is defined to hold Fruit, but how can I not give fruit to it after I initialized it with apple?
class Fruit{}
class Apple extends Fruit{}
class Jonathan extends Apple{}
class Orange…
Kun Peng
- 1
0
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0 answers
C++ avoid casting in derived class code for twin container/contained object design
I have twin base classes for a container class and contained object (in my case, for a generic graph class made of linked nodes, but I guess the question would stand in all cases where you want to derive from both a container class and a contained…
LMNCA
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UpCasted field without access
How can I access a field in a UpCasted Object? I cannot use Console.WriteLine in order to print SuperPower property of a Guy object
namespace Test
{
class Guy
{
public int Power { get; set; }
}
class BigGuy : Guy
{
…
K.Zoyar
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0
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4 answers
How to Access Parent Method using an Upcast object in JAVA?
I am new to Java and got a doubt regarding Upcasting and Down-Casting.
I have written the following code:
class Bike{
int speedlimit=90;
int bikeId = 123576;
Bike(){
System.out.println("inside Bike");} //end constructor
public void run(){…
Raj Sawant
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Confusion regarding upcasting in Java
I am writing a networking code in java and It looks like following:
//Declaring the reference variable
HttpsURLConnection httpsURLConnection = null;
AuthHttpURLConnection authHttpURLConnection = null;
httpsURLConnection =…
java_doctor_101
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Qt: Upcasting a signal's parameter to the slot
I have a signal that is emitted w/a parameter taken from a subclass, but in one slot implementation, I don't need a special handler for the subclass; just the parent class. I thought that connect() would upcast that parameter, but unfortunately, I…
Opux
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How does Dynamic (run-time) polymorphism work in java? In other words how does the JVM know which methods to call?
Say you have an arrayList of objects ArrayList
Aleksandr Diamond
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0
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convert a integer to array of class type java
I take in a file which has a name (table) and the number of seats:
table1 6
table2 2
table3 4
I have an array of class Reservation which will take in the the name and the seat. I am having trouble converting the number of seats into the array. How…
bpham93
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Is it possible to achieve run-time/compile-time polymorphism using downcasting?
I know that upcasting can be used to achieve run-time polymorphism in java. But I am curious about a similar possibility in case of downcasting. If polymorphism is possible in case of downcasting, then is it runtime or compiletime?
The below code is…
Daisy
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Accessing members of class after Upcasting in Java
I am going through my notes(after 5-6 months) and I am unable to understand the output given by following code :
class Base
{
int x=20;
}
class Child extends Base
{
int x=50;
public static void main(String arg[])
{
Base b…
praggi
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0
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1 answer
Swift: Inheritance in type parameters
I'm trying to cast an object of a class with a type parameter into an object of the same class with a more generic type parameter, as illustrated in the following Swift code:
class ParameterClassA {
}
class ParameterClassB: ParameterClassA…
David
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