Rust Function: Check character case

Last update on December 21 2024 10:22:37 (UTC/GMT +8 hours)

Write a Rust function that takes a string slice and returns "Uppercase characters!" if all characters are uppercase, "Lowercase characters!" if all characters are lowercase, and "Mixedcase characters!" otherwise.

Sample Solution:

Rust Code:

// Function to determine the case of characters in a string slice.
fn check_case(s: &str) -> &'static str {
    // Check if the string is empty
    if s.is_empty() {
        // If empty, return "Empty string!"
        return "Empty string!";
    }

    // Check if all characters are uppercase
    let is_uppercase = s.chars().all(|c| c.is_uppercase());
    // Check if all characters are lowercase
    let is_lowercase = s.chars().all(|c| c.is_lowercase());

    // If all characters are uppercase, return "Uppercase characters!"
    if is_uppercase {
        "Uppercase characters!"
    // If all characters are lowercase, return "Lowercase characters!"
    } else if is_lowercase {
        "Lowercase characters!"
    // Otherwise, return "Mixedcase characters!"
    } else {
        "Mixedcase characters!"
    }
}

fn main() {
    // Example usage
    let uppercase_str = "RUST";
    let lowercase_str = "exercises";
    let mixedcase_str = "HeLlO";

    println!("{}", check_case(uppercase_str)); // Output: Uppercase characters!
    println!("{}", check_case(lowercase_str)); // Output: Lowercase characters!
    println!("{}", check_case(mixedcase_str)); // Output: Mixedcase characters!
}

Output:

Uppercase characters!
Lowercase characters!
Mixedcase characters!

Explanation:

The above code defines a function "check_case()" that takes a string slice 's' as input and determines the case of characters in the string.

• The function first checks if the input string is empty. If it is, it returns "Empty string!".
• It then checks if all characters in the string are uppercase using the "all()" method on the iterator returned by "chars()". If all characters are uppercase, it returns "Uppercase characters!".
• Next, it checks if all characters in the string are lowercase using a similar approach. If all characters are lowercase, it returns "Lowercase characters!".
• If neither of the above conditions is met, it concludes that the string contains a mix of uppercase and lowercase characters, and it returns "Mixedcase characters!".

In the "main()" function, example strings of different cases are created and passed to the "check_case()" function. The result of each call to "check_case()" is printed.

Rust Code Editor:

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