Question

Suppose that classstanding is a char variable, and gpa and dues are double variables. Write a switch expression that assigns the dues as following: If classStanding is ' \(\mathrm{f}\) ', the dues are \(\$ 150.00 ;\) if classstanding is 's' (if gpa is at least 3.75 , the dues are \(\$ 75.00 ;\) otherwise, dues are 120.00 ); if classStanding is 'j' (if gpa is at least 3.75, the dues are \(\$ 50.00\) otherwise, dues are \(\$ 100.00\) ); if classstanding is 'n' (if gpa is at least \(3.75, \text { the dues are } \$ 25.00 ; \text { otherwise, dues are } \$ 75.00) .\) (Note that the code 'f' stands for first year students, the code 's' stands for second year students, the code 'j' stands for juniors, and the code 'n' stands for seniors.)

Short answer

Use a switch case to set `dues` based on `classstanding` and `gpa`. Each case ('f', 's', 'j', 'n') has specific rules.

Step-by-step solution

Understand the Requirements

We need to assign a value to the variable `dues` based on the value of `classstanding`, which can be 'f', 's', 'j', or 'n'. Furthermore, for certain class standings ('s', 'j', 'n'), the `gpa` value will influence the amount of `dues` assigned.

Create the Switch Structure

Start creating a switch structure in your preferred programming language. The `switch` statement will evaluate the variable `classstanding` to determine which case to execute.

Define Case for 'f'

In the switch expression, define the case where `classstanding` is 'f'. In this case, directly assign the value of 150.00 to `dues`.

Define Case for 's'

For the case where `classstanding` is 's', check the GPA. If `gpa >= 3.75`, then assign `dues = 75.00`; otherwise, assign `dues = 120.00`.

Define Case for 'j'

In the case where `classstanding` is 'j', check if `gpa >= 3.75`. If true, then `dues = 50.00`; if false, assign `dues = 100.00`.

Define Case for 'n'

For seniors, when `classstanding` is 'n', check the GPA. If `gpa >= 3.75`, assign `dues = 25.00`; otherwise, `dues = 75.00`.

Finalize Each Case with Break

Ensure each case ends with a `break` statement to prevent fall-through. This keeps the operation within its respective case scenario.

Key concepts

char variable

A char variable is used to store a single character from the character set defined by the programming language you're using. In many languages like C++ or Java, a char variable takes up one byte of memory, which is enough to hold a character such as 'a', '1', or even a punctuation mark like '!'.
An example of declaring a char variable is:

• char classStanding;

In our exercise, we use a char variable named classstanding to represent the year of a student's study using just one letter: 'f' for first-year, 's' for second-year, 'j' for juniors, and 'n' for seniors. This helps simplify coding when you need to perform operations based on a specific category.

When using char variables, it's essential to remember that the comparison is typically case-sensitive. So 'A' and 'a' would be different in character representation, which is important when building logic involving char variables in control structures like the switch statement.

double variables

Double variables are used to store decimal numbers with double-precision floating-point format. This is especially useful when you need to keep track of numbers requiring a great deal of precision, like financial calculations, scientific computations, or in our case, variables such as GPA and dues.
Let's declare double variables:

• double gpa;
• double dues;

In our exercise scenario, the student GPA is assessed, and dues are determined based on GPA values with precise decimal points. As Double precision, these variables can store large numbers of digits both before and after the decimal point, an important feature when dealing with precise financial amounts.

Keep in mind, though, that operations involving floating-point calculations can sometimes result in rounding errors. Thus, always be cautious in coding scenarios where absolute precision is crucial, and consider validating the outputs where necessary.

conditional logic

Conditional logic forms the backbone of decision-making in programming. It allows your code to execute different operations or commands depending on certain conditions—often involving relational operators like '>' (greater than), '<' (less than), or '==' (equal to).

In our exercise, we need to incorporate conditional checks using the GPA for determining dues based on class standing. For example:

• If classstanding is 's' and gpa >= 3.75, then the dues are $75.00; otherwise, they are $120.00.

This structure requires an understanding of combined conditions, using operators like ">=" to ensure correct comparison between real numbers.

Most languages support an 'if-else' structure for conditional logic, but this can also be integrated within strategic control structures like the 'switch' statement, enriching the code's readability and efficiency when multiple conditions depend on a single variable.

control structures

Control structures in programming dictate the flow of control through code. They are essential for implementing complex logic like loops or condition-driven paths.

In this exercise, our focus is on the switch statement, a powerful control structure. The switch statement evaluates a variable (in our case, classstanding) and executes code blocks based on its value. Here's a setup example:

• switch (classstanding) { case 'f': ... break; case 's': ... break; }

The switch structure is best used when you have to execute different operations based on one variable having several discrete possible values (i.e., cases).

In our exercise, the switch statement evaluates and breaks down the char values ('f', 's', 'j', 'n'), executing dues calculations for the corresponding case. Always remember to include a break statement within each case to avoid 'fall-through,' where subsequent cases might unintentionally execute without this separation.