c语言初学者，请教一下问题
输入一个日期，日期格式为：XXXX.XX.XX，判断这一天是这一年的第几天？例如：输入2016.04.11，程序输出“2016.04.11是2016年的第102天”，这里102=31+29+31+11。要求：用switch语句实现。
你要求的程序如下：
#include<stdio.h>
main()
{ int year,month,day,days,leap;
printf("Please enter date(XXXX.XX.XX):");
scanf("%d.%d.%d",&year,&month,&day);
if((year%400==0)||(year%4==0&&year%100!=0) )
leap=1;
else
leap=0;
days=day;
switch( month-1)
{ case 11:days+=30;
case 10:days+=31;
case 9:days+=30;
case 8:days+=31;
case 7:days+=31;
case 6:days+=30;
case 5:days+=31;
case 4:days+=30;
case 3:days+=31;
case 2:
if(leap==1)
days+=29;
else
days+=28;
case 1:days+=31;
}
printf("%d year %d month %d day It's %d day of the year.
",year,month,day,days);
}
程序的运行结果如下：
if (year > 0 && month > 0 && month < 13 && day > 0 && day < 32) {
for (int i = 1; i < month; i++) {
switch (i) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
days = 31;
break;
case 4:
case 6:
case 9:
case 11:
days = 30;
break;
case 2: {
if ((year % 4 == 0 && year % 1 != 0) || (year % 400 == 0)) {
days = 29;
} else {
days = 28;
}
break;
}
}
count = count + days;
}
count = count + day;
System.out.println(year + "年" + month + "月" + day + "日是" + year + "年的第" + count + "天");
} else
System.out.println("数据输入错误！");