Project Euler Problem 1 JScript Version

Project Euler Problem 1.js

//単純に加算
var sum = 0;
for (var i = 1; i < 1000; i++) {
    if ((i % 3) == 0) {
        sum += i;
    } else if ((i % 5) == 0) {
        sum += i;
    }
}
WScript.Echo(sum);
 
//等差数列の和
sum = 0
var a_list = [3, 5, 15];
for (var i in a_list) {
    var a = a_list[i];         //初項, 公差
    var n = parseInt(999 / a); //項数
    var l = n * a;             //末項 a＋(n－1)d
 
    switch (i) {
        case "0":
        case "1": sum += ((a + l) * n / 2); break;
        default:  sum -= ((a + l) * n / 2); break;
    }
}
WScript.Echo(sum);