ソフトウェア開発をシンプルにする考え方のコツ（3/5） - ＠ITpublic class Date { int year = 2000; int month = 1; int day = 1; public Date(int year, int month, int day) { this.year = year ; this.month = month; this.day = day ; if (year < 1) throw new ArgumentException(); if (month < 1 || month > 12) throw new ArgumentException(); if (month == 2) { if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) { if (day < 1 || day > 29) throw new Argum
