This lab serves multiple goals:
- To understand how to represent information in a class,
- To understand the design of a class involving static members,
- To convert between different representations without changing the
stored values in the attributes.
A Class for Chemical Elements
In this lab, you will study and modify a class for chemical
elements. Consult
https://www.wikiwand.com/en/List_of_chemical_elements#List for a
complete list of all elements.
Reading
Download
ChemElemProject
and extract the project. Open it in your IDE, compile, and execute it.
Now read the code in “ChemElem.cs” and “Program.cs”.
The class definition “ChemElem.cs” contains:
- Three attributes,
- One constructor,
- One static method,
- One method that returns the melting point in Celsius, and
- One
ToString method.
The application program “Program.cs” performs one simple conversion from
Kelvin to Celsius. It uses data given by the user to create and display
a ChemElem object (implicitly calling the ToString method).
Modifying
Do the following:
- In “ChemElem.cs”, write getters and setters for all attributes
- In “ChemElem.cs”, write a constructor that requires no arguments.
- In “Program.cs”, create a second object using the custom constructor
that takes 3 arguments, then display the value of its attributes
using the getters you previously defined.
- In “Program.cs”, create an object using the no-args constructor, and
set its values using the setters you previously defined.
- In “Program.cs”, display on the screen the string returned by the
ToString method when it is called by the object you created in the
previous step.
- In “Program.cs”, try calling the
FromKelvinToCelsius method with
one of your objects, for instance using
hydrogen.FromKelvinToCelsius(34). What happens?
- Still in “Program.cs”, try calling the
MeltingInCelsius method
with the class, for instance using ChemElem.MeltingInCelsius();.
What happens?
Enhancing
We now want to significantly improve this class, by adding:
- An attribute for the boiling point,
- All the tools needed to display the information in Fahrenheit
degrees, in addition to Celsius and Kelvin.
You may want to comment out part or all of your “Program.cs” file before
starting to change your class.
- Add an attribute for the boiling point (in Kelvin).
- Modify the constructor, so that it takes a 4th argument, and sets its
value to be the value of the boiling point attribute.
- Create a static
FromKelvinToFahrenheit method, taking inspiration
from the FromKelvinToCelsius method.
- Create a
MeltingInFahrenheit method, that returns the melting point
in Fahrenheit of the calling object. This method should use your
FromKelvinToFahrenheit method.
- Create a
BoilingInFahrenheit method, that returns the boiling point
in Fahrenheit of the calling object. This method should use your
FromKelvinToFahrenheit method.
- Modify the
ToString method, so that the string returned includes
- The name of the chemical element and its atomic number,
- The melting point in Kelvin and Fahrenheit,
- The boiling point in Kelvin and Fahrenheit.
You should test all of those modifications in your “Program.cs” file as
you implement them. Use relevant data, test your program, and make sure
the behavior is the expected behavior.
Elements of solution
Typically, you need to replace
``` csharp
public ChemElem(int atomicNumberParam, string nameParam, decimal meltParam)
```
by
``` csharp
public ChemElem(int atomicNumberParam, string nameParam, decimal meltParam, decimal boilParam)
```
and to add
``` csharp
boil = boilParam;
```
to your constructor.
More subtle, the `FromKelvinToFahrenheit` method can be defined as
follows and then re-used:
``` csharp
public static decimal FromKelvinToFahrenheit(decimal kelvinParam)
{
return kelvinParam * 9/5 - 459.67M;
}
public decimal MeltingInFahrenheit()
{
return FromKelvinToFahrenheit(melt);
}
public decimal BoilingInFahrenheit()
{
return FromKelvinToFahrenheit(boil);
}
```