}
dayOfWeek = GetDayOfWeek(year,month,day); ShowDayOfWeek(year,month,day,dayOfWeek);
private static int InputYear(){ int year; Scanner sc = new Scanner(System.in); System.out.println(\请输入年份：（如：2008）：\ year = sc.nextInt(); }
return year;
private static int InputMonth(){ int month; }
Scanner sc = new Scanner(System.in);
System.out.println(\请输入月份：1-12：\month = sc.nextInt(); return month;
private static int InputDay(){ int day; }
Scanner sc = new Scanner(System.in);
System.out.println(\请输入天数：1-31：\day = sc.nextInt(); return day;
private static String GetDayOfWeek(int y,int m,int d){ int h; h = CalculateH(y,m,d); String dayOfWeek;
switch (h) { case 0: dayOfWeek = \星期六\ case 1: dayOfWeek = \星期日\
case 2: dayOfWeek = \星期一\ case 3: dayOfWeek = \星期二\ case 4: dayOfWeek = \星期三\ case 5: dayOfWeek = \星期四\ case 6: dayOfWeek = \星期五\ default: dayOfWeek = \星期计算错误\ } return dayOfWeek; } private static int CalculateH(int year,int month,int day){ int h,q,m,j,k; q = day; if (1 == month){ m = 13; k = year % 100 -1; }else if (2 == month){ m = 14; k = year % 100 -1; }else{ m = month; k = year % 100; } j = Math.abs(year/100); h = (q + (int)(26*(m + 1)/10) + k + (int)(k/4) + (int)(j/4) + 5 * j) % 7; return h; } private static void ShowDayOfWeek(int year,int month,int day, String dayOfWeek){ System.out.println(year+\是\ } } 3_24 /**
（游戏，挑一张牌）编写程序，模拟从一副52张的牌中选择一张牌。程序应该显示牌的大小
（A，2，3，4，5，6，7，8，9，10，J，Q，K）以及牌的花色（黑梅花，红方块，红心，
黑桃）。 */
public class chap3_24{ public static void main(String[] args){ String colorOfPoker; String size; ShowMessage(\正在挑牌，请您耐心等待...\ colorOfPoker = RandomSelectColor(); size = RandomSelectSize(); ShowMessage(\为您挑出的牌是：\ } private static String RandomSelectSize(){ String size; int num; num = (int)(Math.random()*13) + 1; switch (num){ case 1: size = \ case 2: size = \ case 3: size = \ case 4: size = \ case 5: size = \ case 6: size = \ case 7: size = \ case 8: size = \ case 9: size = \ case 10: size = \ case 11: size = \ case 12: size = \ case 13: size = \ default: size = \错误的大小\ } return size; } private static String RandomSelectColor(){
String color; int num; num = (int)(Math.random()*4); switch (num){ case 0: color = \黑梅花\ case 1: color = \红方块\ case 2: color = \红心\ case 3: color = \黑桃\ default:color = \错误的花色\ } return color; } private static void ShowMessage(String message){ System.out.println(message); } } 4_19 /**
(打印金字塔形的数字)编写一个嵌套的for循环，打印下面的输出： */ /**
人工解决问题的分析： 约束条件分析：
1、需要提供塔高即行数lineAmount 2、主观限定lineAmountr<=10
3、主观限定每个数字的宽度widthOfNumber=4 4、数字右对齐
5、每个数字的类型为int 算法分析：
1. 循环打印各行（外层循环）, 循环次数为lineAmount，循环变量为 i，（i=0,1,...,lineAmount-1） 1.1. 循环打印每一行（内层循环）, 循环次数为2i+1，循环变量为j，（j=0,1,...,2i） 1.1.1. 计算打印的数字, 设数字为number，指数为index，number=（int）Math.pow（2，index） 1.1.1.1. 计算index 当j<=i时，index=j；当年j>i时，index=i-1,i-2,...,0 如i=7时： j: 0,1,2,3,4,5,6,7, 8, 9, 10, 11, 12, 13, 14 index: 0,1,2,3,4,5,6,7, 6, 5, 4, 3, 2, 1, 0 1.1.2. 在每一行前面输出若干空格
