Warm-up Exercises

Consider the following partial class definition:

public class Book
{
    private string title;
    private string author;
    private string publisher;
    private int copiesSold;
}

Write a statement that would create a Book object.
Write a “getter” and a “setter” for the title attribute.
Write a constructor for the Book class taking at least one argument.

Solution for Part 1

Book myBook = new Book();

Solution for Part 2

public string GetTitle()
{
    return title;
}
 
public void SetTitle(titleP)
{
    title = titleP;
}

Solution for Part 3

public Book(string titleP, string authorP)
{
    title = titleP;
    author = authorP;
}

Questions

How do you make reference to a public property Name outside of the class (for instance, in the Main method)?

*Name
+Name
.Name
None of these

In C#, you should think of the class’s properties as the class’s attributes.

Yes
No

The property notation allows the client to directly manipulate the private instance variable.

Yes
No

Consider the code:

public void SetName(string tempAccountName)
{
name = tempAccountName; // store the account name
}

Which of the following statements is false? - [ ] The first line of each method declaration is the method header. - [ ] The method’s return type specifies the type of data the method returns to its caller after performing its task. - [ ] The return type void indicates that when SetName() completes its task, it does not return any information to its calling method. - [x] All methods require at least one parameter to provide data to perform tasks.

A return type of _____ is specified for a method that does not return a value.

int
double
void
None of the above.

Methods are called by writing the name of the method followed by _____ enclosed in parentheses.

a condition
argument(s)
a counter
None of the above.

The parameter list in the method header and the arguments in the method call must agree in:

Number
Type
Order
All of the above

Suppose method1 is declared as

public void method1(int a, float b, string c)

Which of the following methods does not overload method1? - [x] void method2(int a, float b, char c) - [ ] int method1(float a, int b, string c) - [ ] float method1(int a, float b) - [ ] string method1(string a, float b, int c)

Write a get method for an instance variable named total of type int.

Solution

public int GetTotal()
{
    return total;
}

Write a getter for an attribute of type string named myName.

Solution

public string GetMyName()
{
    return myName;
}

Write a setter for an attribute of type int named myAge.

Solution

public void SetMyAge(int age)
{
    myAge = age;
}

Assuming name is a string instance variable, there is a problem with the following setter. What is the problem, and how would one fix it?

public int SetName1(string var){
    name = var;
}

Solution

The keyword var is being used as an identifier.

public int SetName1(string nameVar)
{
    name = nameVar;
}

Is it possible to have more than one constructor defined for a class? If yes, how can C# know which one is called?

Solution

Yes, C# can identify which constructor is called based on that constructor’s method signature, that is, the combination of parameters associated with it.

What is the name of a constructor method? What is the return type of a constructor?

Solution

The name of a constructor method is the name of the class that contains it, and a constructor’s return type is the class that contains it.

Write a constructor for a Soda class with one string attribute called name.

Solution

public Soda(string nameP)
{
    name = nameP;
}

What is the “default” constructor? Do we always have the possibility of using it?

Solution

The default constructor is one without any parameters. The only case in which it may not be called is if it has not been explicitly defined while other constructors have been defined.

Why would one want to define a constructor for a class?

Solution

By defining a constructor for a class, one can specify which values to assign to the instance variables upon instantiation.

Problems