JS——輸入一個日期判斷該日期為當年的第幾天

JS——輸入一個日期判斷該日期為當年的第幾天

let read =require("readline-sync");
console.log("輸入年份");
let year=read.question("");
console.log("輸入月份");
let mon=read.question("");
console.log("輸入日期");
let day=parseInt(read.question(""))
let num=0
switch (mon-1) {
    case 11:num+=30;
    case 10:num+=31;
    case 9: num+=30;
    case 8: num+=31;
    case 7: num+=31;
    case 6: num+=30;
    case 5: num+=31;
    case 4: num+=30;
    case 3: num+=31
    case 2:{
        if (year%4==0) {
            num+=29;
        }else{
            num+=28
        }
    }
    case 1:num+=31  
}
console.log(num + day+"天");