Exercise: Day of the Week (Switch & Functions in Go)

Exercise Overview:

We will create a program that:

• Allows the user to enter a number (1-7) and returns the corresponding day of the week.
• Checks whether the day is a weekday or a weekend.
• Displays all days of the week.
• Uses functions and a switch statement for better code organization.

Step 1: Creating the Menu

Before implementing the functionality, we need a menu that allows users to choose options. This menu will loop until the user chooses to quit.

Code Implementation:

package main

import (
    "fmt"
)

// Function to display the menu
func displayMenu() {
    fmt.Println("\nSelect an option:")
    fmt.Println("1. Enter a number (1-7) to get the day name")
    fmt.Println("2. Check if a day is a weekday or weekend")
    fmt.Println("3. Show all days of the week")
    fmt.Println("4. Quit")
}

func main() {
    var choice int

    for {
        displayMenu()
        fmt.Print("Enter your choice: ")
        fmt.Scanln(&choice)

        switch choice {
        case 1:
            fmt.Println("Feature: Get day name - To be implemented")
        case 2:
            fmt.Println("Feature: Check if weekday/weekend - To be implemented")
        case 3:
            fmt.Println("Feature: Show all days - To be implemented")
        case 4:
            fmt.Println("Goodbye!")
            return
        default:
            fmt.Println("Invalid choice! Please enter a number between 1 and 4.")
        }
    }
}

Step 2: Getting the Day Name

Code Implementation:

func getDayName(day int) string {
    switch day {
    case 1:
        return "Monday"
    case 2:
        return "Tuesday"
    case 3:
        return "Wednesday"
    case 4:
        return "Thursday"
    case 5:
        return "Friday"
    case 6:
        return "Saturday"
    case 7:
        return "Sunday"
    default:
        return "Invalid day number! Please enter a number between 1 and 7."
    }
}

Step 3: Checking if the Day is a Weekday or Weekend

Code Implementation:

func isWeekend(day int) string {
    switch day {
    case 6, 7:
        return "It's a weekend!"
    case 1, 2, 3, 4, 5:
        return "It's a weekday."
    default:
        return "Invalid day number! Please enter a number between 1 and 7."
    }
}

Step 4: Displaying All Days of the Week

Code Implementation:

func showAllDays() {
    days := []string{"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"}
    fmt.Println("\nDays of the week:")
    for i, day := range days {
        fmt.Printf("%d. %s\n", i+1, day)
    }
}

Final Testing & Full Code

Final Code:

package main

import (
    "fmt"
)

func displayMenu() {
    fmt.Println("\nSelect an option:")
    fmt.Println("1. Enter a number (1-7) to get the day name")
    fmt.Println("2. Check if a day is a weekday or weekend")
    fmt.Println("3. Show all days of the week")
    fmt.Println("4. Quit")
}

func getDayName(day int) string {
    switch day {
    case 1:
        return "Monday"
    case 2:
        return "Tuesday"
    case 3:
        return "Wednesday"
    case 4:
        return "Thursday"
    case 5:
        return "Friday"
    case 6:
        return "Saturday"
    case 7:
        return "Sunday"
    default:
        return "Invalid day number! Please enter a number between 1 and 7."
    }
}

func isWeekend(day int) string {
    switch day {
    case 6, 7:
        return "It's a weekend!"
    case 1, 2, 3, 4, 5:
        return "It's a weekday."
    default:
        return "Invalid day number! Please enter a number between 1 and 7."
    }
}

func showAllDays() {
    days := []string{"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"}
    fmt.Println("\nDays of the week:")
    for i, day := range days {
        fmt.Printf("%d. %s\n", i+1, day)
    }
}

func main() {
    var choice int

    for {
        displayMenu()
        fmt.Print("Enter your choice: ")
        fmt.Scanln(&choice)

        switch choice {
        case 1:
            fmt.Print("Enter a number (1-7): ")
            var day int
            fmt.Scanln(&day)
            fmt.Println("The day is:", getDayName(day))
        case 2:
            fmt.Print("Enter a number (1-7): ")
            var day int
            fmt.Scanln(&day)
            fmt.Println(isWeekend(day))
        case 3:
            showAllDays()
        case 4:
            fmt.Println("Goodbye!")
            return
        default:
            fmt.Println("Invalid choice! Please enter a number between 1 and 4.")
        }
    }
}