error-handling-quiz.md

Quiz: Effective Error Handling in Go

Which of the following accurately describes how errors are returned and treated in Go?

• Errors are displayed as pop-up messages.
• Errors are returned as values from functions.
• Errors are automatically corrected by the runtime.
• Errors are stored in a global variable.

Note

Errors are returned as values from functions meaning that they can be handled similarly to any other datatype.

Which of the following best describes the purpose of the built-in error type in Go?

• Check for error conditions and return true or false.
• Store error codes and messages in a struct.
• Define common error messages used in Go programs.
• Represent an error condition with a descriptive message.

Note

The built-in error type in Go is an interface designed to represent an error condition with a descriptive message.

In the provided code snippet, what is the purpose of creating a custom error type CustomError?

type CustomError struct {
    Code    int
    Message string
}

func NewCustomError(code int, message string) *CustomError {
    return &CustomError{Code: code, Message: message}
}

func main() {
    err := NewCustomError(404, "Not Found")
    if err != nil {
        fmt.Println("Error Code:", err.Code, "Message:", err.Message)
    }
}

• To automatically log errors to a file
• To replace the built-in error type in Go
• To handle errors without using the error interface
• To embed additional context or information within error messages

Note

The CustomError struct allows developers to include additional information like error codes and messages to provide more context about the error.

Complete the following code to demonstrate the use of panic() and recover() functions:

func main() {
    defer func() {
        if r := recover(); r != nil {
            fmt.Println("Recovered from panic:", r)
        }
    }()

    startApplication()
    fmt.Println("Application started successfully")
}

func startApplication() {
    if _, err := os.Stat("app.config"); os.IsNotExist(err) {
        panic("Application configuration file is missing")
    }
    fmt.Println("Configuration loaded successfully")
}

Note

panic() prints a panic message and begins unwinding the stack, then runs deferred functions and terminates the program. recover() is used to recover from a panic and resume normal execution.

In the provided code snippet, what does the %w in fmt.Errorf do?

func readFile(filename string) error {
    originalErr := errors.New("file not found")
    return fmt.Errorf("failed to read file: %w", originalErr)
}

• It prints the error message in uppercase.
• It logs the error to a file.
• It wraps the original error with additional context.
• It converts the error message to a warning.

Note

The %w in fmt.Errorf is used to wrap the original error with more context, preserving the original error information.