https://doc.rust-lang.org/std/fmt/#fillalignment ```rust let x = "100"; // 右寄せ8桁 assert_eq!(format!("{x:>8} end"), " 100 end"); // 左寄せ8桁 assert_eq!(format!("{x:<8} end"), "100 end"); // 中央寄せ8桁 assert_eq!(format!("{x:^8} end"), " 100 end"); // ゼロ埋め右寄せ8桁 assert_eq!(format!("{x:0>8} end"), "00000100 end"); // *埋め左寄せ8桁 assert_eq!(format!("{x:*<8} end"), "100***** end"); ```