Rust Function: Process result handling

Last update on December 21 2024 10:20:16 (UTC/GMT +8 hours)

Write a Rust function that takes a Result and returns the integer if it's Ok(i32) and converts the string to uppercase if it's Err(&str).

Sample Solution:

Rust Code:

// Function that processes a Result<i32, &str> and returns either the integer if it's Ok(i32)
// or the uppercase version of the string if it's Err(&str).
fn process_result(result: Result<i32, &str>) -> String {
    // Use a match expression to handle both Ok and Err variants of the Result
    match result {
        // If the Result is Ok(i32), return the integer
        Ok(num) => num.to_string(),
        // If the Result is Err(&str), convert the string to uppercase and return it
        Err(s) => s.to_uppercase(),
    }
}

fn main() {
    // Example usage
    let ok_result: Result<i32, &str> = Ok(200);
    let err_result: Result<i32, &str> = Err("error message!");

    println!("{}", process_result(ok_result)); // Output: 42
    println!("{}", process_result(err_result)); // Output: ERROR MESSAGE
}

Output:

200
ERROR MESSAGE!

Explanation:

In the exercise above,

• The "process_result()" function takes a Result<i32, &str> as input and returns a String.
• Inside the function, a 'match' expression is used to handle both the 'Ok' and 'Err' variants of the 'Result'.
• If the 'Result' is 'Ok(i32)', the function converts the integer to a string using "to_string()" and returns it.
• If the 'Result' is 'Err(&str)', the function converts the string to uppercase using to_uppercase() and returns it.
• In the "main()" function, example 'Result' values are created and passed to "process_result()", and the result of each call is printed.

Rust Code Editor:

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