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If not, it may be possible to perform a cast on the value to change its type and assign it to the variable as the new type.

Successful cast depends on class hierarchy

With regard to reference types, whether or not a cast can be successfully performed depends on the relationship of the classes involved in the classhierarchy.

The generic type Object

A reference to any object can be assigned to a reference variable of the type Object , because the Object class is a superclass of every other class.

In other words, an object instantiated from any class is assignment-compatible with the type Object .

Calling a method on an object

Whether or not a method can be called on a reference to an object depends on the current type of the reference and the location in the class hierarchy where the method is defined.

In order to use a reference of a class type to call a method, the method must be defined at or above that class in the class hierarchy.

Assignment compatibility and type conversion

As background, for understanding runtime polymorphism, you need to understand assignment compatibility and type conversion .

As I mentioned earlier, a value of a given type is assignment-compatible with another type if a value of the first type can be successfully assigned to avariable of the second type.

Type conversion and the cast operator

In some cases, type conversion happens automatically. In other cases, type conversion must be forced through theuse of a cast operator.

A cast operator is a unary operator, which has a single right operand. The physical representation of the cast operator is the name of a type enclosed by apair of matching parentheses, as in:

(int)

Applying a cast operator

Applying a cast operator to the name of a variable doesn't actually change the type of the variable. However, it does cause the contents of the variable tobe treated as a different type for the evaluation of the expression in which the cast operator is contained.

Primitive values and type conversion

Assignment compatibility issues come into play for both primitive types and reference types.

Boolean types

To begin with, values of type bool can only be assigned to variables of type bool (you cannot change the type of a bool ). Thus, a value of type bool is not assignment-compatible with a variable of any other type.

Numeric primitive types

In general, numeric primitive values can be assigned to (are assignment-compatible with) a variable of a type whose numeric range is as wideas or wider than the range of the type of the value. In that case, the type of the value is automatically converted to the type of the variable.

For example, types sbyte and short can be assigned to a variable of type int , because type int has a wider range than either type sbyte or type short .

On the other hand, a primitive numeric value of a given type cannot be assigned to (is not assignment-compatible with) a variable of a type with anarrower range than the type of the value.

However, it is possible to use a cast operator to force a type conversion for numeric primitive values.

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Xna game studio. OpenStax CNX. Feb 28, 2014 Download for free at https://legacy.cnx.org/content/col11634/1.6
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