Fmt Enums

Formatting enums

Alignment Enum

use std::fmt::{self, Formatter, Alignment};

struct AlignDemo(i32);

impl fmt::Display for AlignDemo {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        // Get alignment from format specifier
        let align = f.align();
        let width = f.width().unwrap_or(0);

        let s = self.0.to_string();

        match align {
            Some(Alignment::Left) => write!(f, "{:<width$}", s),
            Some(Alignment::Right) => write!(f, "{:>width$}", s),
            Some(Alignment::Center) => write!(f, "{:^width$}", s),
            None => write!(f, "{}", s),
        }
    }
}

fn main() {
    println!("=== Alignment Enum ===");
    println!("Alignment::Left   - '<'");
    println!("Alignment::Right  - '>'");
    println!("Alignment::Center - '^'");

    let val = AlignDemo(42);

    println!("\n=== With width 10 ===");
    println!("Left:   [{:<10}]", val);
    println!("Right:  [{:>10}]", val);
    println!("Center: [{:^10}]", val);

    // With fill character
    println!("\n=== With fill ===");
    println!("Left:   [{:*<10}]", 42);
    println!("Right:  [{:*>10}]", 42);
    println!("Center: [{:*^10}]", 42);
}