Question

Write a program that allows a user to enter a string containing a day of the week ("Sunday," "Monday," "Tuesday," etc.) and uses a switch construct to convert the day to its corresponding number, where Sunday is considered the first day of the week and Saturday is considered the last day of the week. Print out the resulting day number. Also, be sure to handle the case of an illegal day name! (Note: Be sure to use the 's' option on function input so that the input is treated as a string.)

Short answer

To create a program that converts a day of the week (as a string) to its corresponding number using a switch construct, follow these steps: 1. Get user input for the day of the week and store it as a string variable. 2. Convert the string input to lowercase for easy comparison. 3. Create a switch construct using a dictionary to compare the input with each day of the week and assign the corresponding number. 4. Include a case for handling invalid input and print an error message. 5. Print the day number. Example code in Python: ```python def main(): day = input("Enter a day of the week: ").strip().lower() switch = { "sunday": 1, "monday": 2, "tuesday": 3, "wednesday": 4, "thursday": 5, "friday": 6, "saturday": 7 } day_number = switch.get(day, 'invalid') if day_number == 'invalid': print("Invalid day name!") else: print("The corresponding number is:", day_number) if __name__ == "__main__": main() ``` Note: Python uses a dictionary as an alternative to a native switch construct.

Step-by-step solution

Get user input for the day of the week

Ask the user to enter a day of the week and store it as a string variable.

Convert the string input to lowercase

Convert the given input to lowercase so that it is easier to compare and manage the cases in the switch construct (e.g. "monday", "Monday", "MONDAY" will all be the same).

Create a switch construct

Set up a switch construct to compare the input with each day of the week (in lowercase) and assign the corresponding number for each day, where Sunday is 1 and Saturday is 7.

Case for invalid input

In the switch construct, also create a case for handling invalid input, which will print an error message to inform the user that the input is not a valid day name.

Print the day number

Print out the day number/result of the switch construct. Here's an example code for this program in Python: ```python def main(): day = input("Enter a day of the week: ").strip().lower() switch = { "sunday": 1, "monday": 2, "tuesday": 3, "wednesday": 4, "thursday": 5, "friday": 6, "saturday": 7 } day_number = switch.get(day, 'invalid') if day_number == 'invalid': print("Invalid day name!") else: print("The corresponding number is:", day_number) if __name__ == "__main__": main() ``` Note that Python doesn't have a native switch construct, so we use a dictionary as an alternative.

Key concepts

Day of the Week Conversion

Converting the names of days of the week into numerical values can be especially handy in computing, where you might need to process data in a standardized format.
In this context, the conversion assigns numbers to the days of the week such that:

• Sunday is 1
• Monday is 2
• Tuesday is 3
• Wednesday is 4
• Thursday is 5
• Friday is 6
• Saturday is 7

This numerical representation is useful for operations like comparison of days, sorting, or even graphing.
By doing this conversion through a program, especially using constructs like the MATLAB `switch` statement, you streamline this process, reducing human error and improving consistency. This conversion is simple yet powerful, making your code more versatile when interacting with date-related data.

Input Handling in MATLAB

Handling inputs correctly is crucial when designing robust MATLAB programs. The goal is to correctly interpret what the user types in, ensuring it matches the expected data format.
In this exercise, we deal specifically with string inputs, requiring the 's' flag in MATLAB's `input` function to explicitly denote that an input should be treated as a string.
Here’s how you do it in MATLAB:

• Use `day = input('Enter a day of the week: ', 's');` to ensure the input is a string.
• Handle possible errors or unexpected inputs effectively.
• Consider edge cases like empty strings or unexpected characters and respond accordingly.

Converting the input to lowercase, after capturing it, is a best practice to compare case-insensitively. This aligns with common scenarios where users might enter text in varying cases. Reliable input handling makes your program user-friendly and far less prone to failure when erroneous input is provided.

String Manipulation in MATLAB

String manipulation in MATLAB involves altering, analyzing, or utilizing strings to achieve different outputs. Effective string handling is at the core of many programming challenges, such as parsing inputs or constructing text-based logic.
This exercise requires manipulating a string to identify a day of the week accurately.
Key string manipulations in this context include:

• Converting the string to lowercase using MATLAB’s `lower()` function for uniformity.
• Using the `switch` structure to match and respond to specific string values.
• Returning a value or response based on a string’s specific content, and handling incorrect strings by default in the switch structure.

These manipulations not only improve program accuracy but also ensure that user input is handled in a sophisticated manner, minimizing errors due to capitalization or spacing issues. In MATLAB, `strcomp` can also be used to perform case-insensitive comparisons, bolstering the program’s reliability when working with variable string inputs.