2020-11-08

最新推荐文章于 2025-06-13 08:24:12 发布

爱哭小老虎

最新推荐文章于 2025-06-13 08:24:12 发布

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分类专栏： JS 文章标签： javascript

本文链接：https://blog.youkuaiyun.com/weixin_47583380/article/details/109557714

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输入年份、月份、月份里的天数，算出它是某年的第几天？

 var year = 2020
 var month = 3
 var day = 1
  var sumDay = 0//定义一个总的天数
  //月份倒着来
 switch(month-1){
 case 11:
     sumDay+=30
case 10:
     sumDay+=31
 case 9:
    sumDay+=30
 case 8:
    sumDay+=31
 case 7:
     sumDay+=31
 case 6:
   sumDay+=30
 case 5:
     sumDay+=31
 case 4:
     sumDay+=30
 case 3:
    sumDay+=31
 case 2://三目运算符判断闰年平年
    sumDay+=(year % 400 ==0 || year % 4 ==0 && year % 100 !=0)?29:28
 case 1:
    sumDay+=31
 break
 default:
   console.info("输入错误")
   }
console.info(sumDay+day)

2.采用与运算符，&&前面代码正确执行后续逻辑

 var year = 2020
var month = 3
var day = 1
 var sumDay = 0
 month > 1 &&(sumDay+=31)
 month > 2 &&(sumDay+=(year%400==0 || year % 4 ==0 && year / 100 != 0)?29:28)//三目运算判断
 month > 3 &&(sumDay+=31)
 month > 4 &&(sumDay+=30)
 month > 5 &&(sumDay+=31)
 month > 6 &&(sumDay+=30)
 month > 7 &&(sumDay+=31)
 month > 8 &&(sumDay+=31)
 month > 9 &&(sumDay+=30)
 month > 10 &&(sumDay+=31)
 month > 11 &&(sumDay+=30)
 month > 12 &&(sumDay+=31)
console.log(sumDay + day)