代码：
package com.liron.p1; import java.util.Scanner; /** * 输入某年某月某日，判断这一天是这一年的第几天。 */ public class Topic4 { public static void main(String[] args) throws Exception { int y,m,d; int sum=0; int feb=28; @SuppressWarnings("resource") Scanner in = new Scanner(System.in); System.out.print("请输入年份:"); y = in.nextInt(); System.out.print("请输入月份:"); m = in.nextInt(); System.out.print("请输入几号:"); d = in.nextInt(); if((y%4==0 && y%100!=0) || y%400==0) { feb = 29; } switch(m) { case 1: sum = d; break; case 2: sum = 31 + d; break; case 3: sum = 31+feb+d; break; case 4: sum = 31+feb+31+d; break; case 5: sum = 31+feb+31+30+d; break; case 6: sum = 31+feb+31+30+31+d; break; case 7: sum = 31+feb+31+30+31+30+d; break; case 8: sum = 31+feb+31+30+31+30+31+d; break; case 9: sum = 31+feb+31+30+31+30+31+31+d; break; case 10: sum = 31+feb+31+30+31+30+31+31+30+d; break; case 11: sum = 31+feb+31+30+31+30+31+31+30+31+d; break; case 12: sum = 31+feb+31+30+31+30+31+31+30+31+30+d; } System.out.println(y+" 年 "+m+" 月 " + d + "号是今年的第"+sum+"天"); } }
结果：
