*日历程序*无法为此日历程序编写循环以正确显示

Question

我在尝试完成我的代码时遇到问题。我试图让代码在几个不同的行中打印数组。应该是这样的：

好的，这是更新的代码。我一直在努力，它正在变得更好！但是，我现在的问题是试图弄清楚我需要做什么才能创建代码输出中当前存在“0”和“1”的空格。我想我只需要插入： calDaysOfWeek.unshift(); 或者可能： calDaysOfWeek.shift(); 我只是不知道把它放在哪里。如果我能弄清楚这一点，我应该能够减少代码中的日期缩写（例如 M 到 Mon 或 T 到 Tues）。

/*Write a program called calendar.js that displays a calendar month 
for May 2012 as the month and year. You must use a loop. The format 
of the month should be as shown below: Hint: You can't use console 
log and print on the same line. Try storing the entire row as one 
concatenated string and then displaying it. You must use loops for 
this one. Do not just print the calendar as a series of console.log 
statements!*/


calDaysOfWeek = [];
calDaysOfWeek.push("Sun", "Mon", "Tues", "Wed", "Thur", "Fri", "Sat");

var s = "MAY 2012\nS M T W T F S\n";

var numDaysOfWeek = calDaysOfWeek.length;
var firstDay = 2;
var numDaysOfMonth = 31;
var numWeeks = numDaysOfMonth/7;
for(var i = 0; i < numWeeks; i++) {
 for(var j = 0; j < numDaysOfWeek; j++) {
    s += i*numDaysOfWeek + j + ' ';
}
s += "\n";
}
if (firstDay != calDaysOfWeek[2]) {
calDaysOfWeek.push();
}
else if (calDaysOfWeek[30] != 31) {
    calDaysOfWeek.pop();
}
else
    console.log(s);

Answer 1

这里有一个错误：

for(var i = 0; len = calDaysOfWeek.length; i < len; i++) 

应该是：

len = calDaysOfWeek.length; 

for(var i = 0; i < len; i++) {

}

现在，您需要使用此循环来填充字符串，而不是使用数组。所以：

var s = "";
len = calDaysOfWeek.length; 

for(var i = 0; i < len; i++) {

}

但您的循环仅从 0 变为 6，因为您每周有 7 天。所以你需要在几周内再循环一次。您无法轻松计算的是每月的第一天，即星期二，因此 calDaysOfWeek 中的指数为 2（Sun=0，Mon=1，Tue=2）。您还需要该月的天数，此处为 31。

var s = '';
var numDaysOfWeek = calDaysOfWeek.length;
var firstDay = 2;
var numDaysOfMonth = 31;
var numWeeks = ??? // compute this
for (var i=0; i<numWeeks; i++) {
    for (var j=0; j<numDaysOfWeek; j++) {
         s = ??? // you need to do this
    }
}

一旦结果正确，您可以使用要打印的 html 代码显示它。

编辑：改变循环

Edit2：在fiddle上玩过

calDaysOfWeek = [];
calDaysOfWeek.push("Sun", "Mon", "Tues", "Wed", "Thur", "Fri", "Sat");

var s = "MAY 2012\n";
var numDaysOfWeek = calDaysOfWeek.length;
var firstDay = 2;
var numDaysOfMonth = 31;
var numWeeks = 5; // compute this
for (var i=0; i<numWeeks; i++) {
    for (var j=0; j<numDaysOfWeek; j++) {
         var n = i * numDaysOfWeek + j + 1 - firstDay ;
         if (n < 1 || n > numDaysOfMonth) {
               s += '   '; // three spaces
         }
         else {
             if (n < 10)
             {
                 s += ' '; // pad with one space
             }
             s += n + ' ' ;
         }
    }
    s += "\n";
}


alert(s);