Char Functions

Character manipulation functions

Case Conversion

fn main() {
    // to_lowercase / to_uppercase
    let c = 'a';
    println!("=== Case Conversion ===");
    println!("'a'.to_uppercase(): {:?}", c.to_uppercase().collect::<String>());
    println!("'A'.to_lowercase(): {:?}", 'A'.to_lowercase().collect::<String>());

    // Returns iterator (some chars map to multiple)
    let eszett = 'ß';
    println!("\n'ß' uppercase: {:?}", eszett.to_uppercase().collect::<String>());

    // ASCII versions (single char, faster)
    println!("\n=== ASCII Only ===");
    println!("'a'.to_ascii_uppercase(): {}", 'a'.to_ascii_uppercase());
    println!("'Z'.to_ascii_lowercase(): {}", 'Z'.to_ascii_lowercase());

    // Non-ASCII unchanged
    println!("'ü'.to_ascii_uppercase(): {}", 'ü'.to_ascii_uppercase());

    // Make mutable
    let mut c = 'A';
    c.make_ascii_lowercase();
    println!("\nAfter make_ascii_lowercase: {}", c);

    // Case checks
    println!("\n=== Case Checks ===");
    println!("'A'.is_uppercase(): {}", 'A'.is_uppercase());
    println!("'a'.is_lowercase(): {}", 'a'.is_lowercase());
    println!("'1'.is_uppercase(): {}", '1'.is_uppercase());
}