Question

我试图提示用户输入一个4位数字。然后，更换每个数字乘以（该数字的总和加上7）模数10.然后将第一个数字与第三个数字交换，并将第二个数字与第四个数字交换。然后输出加密的数字。因此，如果我输入1234，它应该加密到0189或输入5948并将其加密到1526

问题是我得到了9810和6251.所以，它向后看它。我很接近，但它的顺序错了。

<script type="text/javascript">


    var temp;
    var number;
    var first;
    var second;
    var third;
    var fourth;
    var fifth;
    //prompt for first number

    do {
        inputNumber = window.prompt("Enter only a 4 digit number");
        if ((isNaN(inputNumber) || !(inputNumber.length == 4)))
            window.alert("please enter a number or length of 4");

    } while ((isNaN(inputNumber)) || !(inputNumber.length == 4));

    //temp = inputNumber;

    temp = parseInt(inputNumber);
    first = temp % 10; //process each number one by one
    temp = temp / 10; 
    second = temp % 10; 
    temp = temp / 10;
    third = temp % 10;
    temp = temp / 10;
    fourth = temp % 10;

    swap = first;
    first = third;
    third = swap;

    swap = second;
    second = fourth;
    fourth = swap;

    first = parseInt(first);
    second = parseInt(second);
    third = parseInt(third);
    fifth = parseInt(fifth);
    fourth = parseInt(fourth);

    first = (first + 7) % 10
    second = (second + 7) % 10
    third = (third + 7) % 10
    fourth = (fourth + 7) % 10

   var incrypted = first * 1000 + second * 100 + third * 10 + fourth * 1;
   //var incrypted = first * 1000 + second  + third * 10 + fourth * 1;
    document.writeln("<h1>The number " + inputNumber + " is encrypted as " + incrypted + ".</h1><br />");

</script>

Answer 1

您可能最好单独处理您的号码。

var digits = inputNumber.split("");
digits[0] = (+digits[0]+7)%10;
digits[1] = (+digits[1]+7)%10;
digits[2] = (+digits[2]+7)%10;
digits[3] = (+digits[3]+7)%10;
digits.push(digits.shift());
digits.push(digits.shift());
// rotating by two results in 1234 becoming 3412, same result just more efficient!
var result = digits.join("");

Answer 2

试

var num = "1234"
var digits = num.split("");
var out = [];
for(var i=0; i<digits.length; i++){
   digits[i] = (parseInt(digits[i])+7)%10;
}
var end = [digits[2],digits[3],digits[0],digits[1]].join("");
console.log(end.join(""));

Answer 3

随机播放功能：

function shuffle(val){
    val = val + "";
    function transform(num) { return (+num + 7) % 10 + ""; }

    return  transform(val[2]) +
            transform(val[3]) +
            transform(val[0]) +
            transform(val[1]);
}

并通过一些验证：

function shuffle(val){
    val = val + "";
    if(isNaN(val)) throw "a valid number is required";
    if(val.length != 4) throw "a four-digit number is required";

    function transform(num) { return (+num + 7) % 10 + ""; }

    return  transform(val[2]) +
            transform(val[3]) +
            transform(val[0]) +
            transform(val[1]);
}

Answer 4

这归结为对%运算符如何工作的基本误解。

MDN引用说明了%运算符：

模数函数是将var1除以var2的整数余数。例如，12％5返回2。

以输入1234为例，您首先在此代码中找到10的模1234：

first = temp % 10;

1234的模数为4，因为1230可以被10整除，剩下4。因此，你的逻辑逆转了事情。你可以在代码的开头改变一些东西来反转：

fourth = temp % 10; //process each number one by one
temp = temp / 10;.
third = temp % 10;.
temp = temp / 10;
second = temp % 10;
temp = temp / 10;
first = temp % 10;

还有一个问题，如果修复如上所述，代码将输出189作为答案，因为您将数字与加法算法而不是字符串连接组合在一起，如0 + 1 + 8 + 9 = 189中所示。将最后一行更改为如下所示并修复：

var incrypted = first + '' + second  + '' + third + '' + fourth;

Answer 5

这对我有用;

<script>
    var vec = new Array("1","2","3","4");

    for(var i = 0; i<4; ++i){
        vec[i] = (+vec[i] + 7) % 10;
    }

    var tmp = vec[1];
    vec[1] = vec[3];
    vec[3] = tmp;

    vec = vec.reverse();

    tmp = Number(vec.splice(0,1));

    vec.push(tmp);

    console.log("vec:", vec);
</script>

记录vec: [0, 1, 8, 9]

输入4位数字并更改订单

5 个答案: