Topic H – Case Structures

Overview

This topic introduces the C# switch statement which is used to code case structures. The following new keywords are introduced.
* switch
* case
* default
* break

LOGs

General Programming Concepts and Terms

• Describe the syntax of the switch statement
• Discuss the limitations of the switch statement in C# and the available alternatives for the times that we can’t use a switch statement

Code Samples

1. LetterGrade - Represents a letter grade as assigned in Quebec universities. Source: http://en.wikipedia.org/wiki/Letter_grade
2. Rating – Represents a rating on a scale of 1 to 5, where 1 is “very bad”, 2 is “bad”, 3 is “average”, 4 is “good”, and 5 is “very good”.

LetterGrade

Problem Statement

Write the code for the LetterGrade class that represents a letter grade as assigned in Quebec universities (Source: http://en.wikipedia.org/wiki/Letter_grade). The solution must meet the following requirements (note – you do not need to perform validation for this sample):

• Should get and set the grade (as a single letter)
• Should ensure the grade is in upper-case
• Should get the appropriate descriptions for the grade, based on the following table:

Use the following class diagram when creating your solution.

 1 public class LetterGrade
 2 {
 3     private char _Grade;
 4 
 5     public char Grade
 6     {
 7         get { return _Grade; }
 8         set { this._Grade = char.ToUpper(value); }
 9     }
10 
11     public LetterGrade(char grade)
12     {
13         Grade = grade;
14     }
15 
16 
17     public override string ToString()
18     {
19         string description;
20         switch (_Grade)
21         {
22             case 'A':
23                 description = "A - 80-100% - Greatly Above Standards";
24                 break;
25             case 'B':
26                 description = "B - 70-79% - Above Standards";
27                 break;
28             case 'C':
29                 description = "C - 60-69% - At Government Standards";
30                 break;
31             case 'D':
32                 description = "D - 50-60% - Lower Standards";
33                 break;
34             case 'F':
35                 description = "F - 0-49% - Failure";
36                 break;
37             default:
38                 description = "Invalid Letter Grade";
39                 break;
40         }
41         return description;
42     }
43 }

Rating

Problem Statement

Write the code for the Rating class that represents a rating on a survey where the rating is done using the values 1 through 5, inclusive. The solution must meet the following requirements (note – you do not need to perform validation for this sample):

• Should get and set the rating value
• Should get the appropriate string result when using the ToString() method, based on the following table:

Use the following class diagram when creating your solution.

 1 public class Rating
 2 {
 3     public int Value { get; set; }
 4 
 5     public Rating(int value)
 6     {
 7         Value = value;
 8     }
 9 
10 
11     public override string ToString()
12     {
13         string rating;
14         switch (Value)
15         {
16             case 5:
17                 rating = "very good";
18                 break;
19             case 4:
20                 rating = "good";
21                 break;
22             case 3:
23                 rating = "average";
24                 break;
25             case 2:
26                 rating = "bad";
27                 break;
28             case 1:
29                 rating = "very bad";
30                 break;
31             default:
32                 rating = "Invalid Rating";
33                 break;
34         }
35         return rating;
36     }
37 }

Practice Exercises

1. BahamaLetterGrade - Represents a letter grade as assigned in the Bahamas universities. Source: http://en.wikipedia.org/wiki/Letter_grade
2. Feedback – Represents an opinion rating as feedback, where 1 is “no opinion”, 2 is “strongly disagree”, 3 is “disagree”, 4 is “agree, and 5 is “strongly agree”.
3. HazardousMaterial – Represents the six hazardous material codes of ‘A’ through ‘F’.

BahamaLetterGrade

Problem Statement

Write the code for the BahamaLetterGrade class that represents a letter grade as assigned in the Bahamas universities (Source: http://en.wikipedia.org/wiki/Letter_grade). Each letter grade is also associated with a grade value. The solution must meet the following requirements (note – you do not need to perform validation for this exercise):

• Should get and set the grade (as a single letter)
• Should ensure the grade is in upper-case
• Should get the appropriate descriptions for the grade, based on the following table:

Use the following class diagram when creating your solution.

Feedback

Represents an opinion rating as feedback, where 1 is “no opinion”, 2 is “strongly disagree”, 3 is “disagree”, 4 is “agree, and 5 is “strongly agree”.

Problem Statement

Write the code for the Feedback class that represents a rating on a survey where the feedback is given using the values 1 through 5, inclusive. The solution must meet the following requirements (note – you do not need to perform validation for this sample):

• Should get and set the feedback value
• Should get the appropriate string result when using the ToString() method, based on the following table:

Use the following class diagram when creating your solution.

HazardousMaterial

The class code for the hazardous material can only be the letters ‘A’ through ‘F’, inclusive.

Problem Statement

Rewrite the code for the HazardousMaterial class to make use of the switch statement. The solution must meet the following requirements (new requirements are in bold):

• Should return the class code as the classification
• Should make sure only class codes ‘A’ through ‘F’ are allowed (in either upper or lower case)
• Should make sure the classification is stored in upper case
• Should get the description for the class, based on the following table
  You must use a switch statement to get the results

• Should override the ToString() method to get the full description and class code in the following format:
  
  • “Class ClassCode - Description”

Use the following class diagram when creating your solution.