console.log("输入年份：");
let year = readline.question() - 0;
console.log("输入一个月份");
let month = readline.question() - 0;
console.log("输入天数");
let day = readline.question() - 0;
if (year > 999 && year < 10000) {
if (month > 0 && month < 13) {
if (day > 0 && day < 30) {
let c = 0;
switch (month - 1) {
case 11: c += 30;
case 10: c += 31;
case 9: c += 30;
case 8: c += 31;
case 7: c += 30;
case 6: c += 31;
case 5: c += 30;
case 4: c += 31;
case 3: c += 30;
case 2: {
if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
c += 29;
} else {
c += 28;
}
}
case 1: c += 31;
}
console.log("在" + year + "中，你输入的是当前第" + (c + day) + "天");
} else {
console.log("天数错误");
}
} else {
console.log("月份错误");
}
} else {
console.log("年份输入错误");
}
用JS写，根据用户输入的年月份判断是这年的第几天
原文地址：https://www.cnblogs.com/yehongrun/p/9060059.html