JavaScript NaN错误循环

JavaScript NaN error loop

本文关键字：循环 错误 NaN JavaScript      更新时间：2023-09-26

运行此代码时收到NaN错误。一段时间以来，我一直在努力找出原因，但一辈子都找不到。

为了澄清，我正在努力接受；

  • 客户的欠款总额

  • 有多少客户进入

    function Summarise()
{
    ID = prompt("Enter a Customer ID number ", -1)
    while(ID != -1) 
    {
        var gasUsed = 0
        var total = 0
        gasUsed = prompt("Enter amount of gas used ", "0")
        ///Standard Rate is used to assist in the calculation of customers in excess of 60 Gas Used
        StandardRate = 60 * 1.75
        if(gasUsed <= 60) 
        {
            total= gasUsed * 2
            document.write("Customers ID: " + ID)
            document.write(" has gas usage of " + gasUsed)
            document.write(" and owes $" + total)
            document.write("<br/>")
        } 
        else 
        {
            total= (gasUsed - 60) * 1.50 + StandardRate
            document.write("Customers ID: " + ID)
            document.write(" has gas usage of " + gasUsed)
            document.write(" and owes $" + total)
            document.write("<br/>")
        }
        var totalowed = total + totalowed
        var totalcustomers = ++totalcustomers
        ID = prompt("Enter a Customer ID number ", -1)
    }
    document.write("Total amount owed $" + totalowed)
    document.write("<br/>")
    document.write("Total Number of customers:" + totalcustomers)

}

您需要在循环之前定义这两个变量：

var totalowed = 0;
var totalcustomers = 0;

当您为它们赋值时，它们最初是未定义的，这总是会产生问题。

你可以看到下面的工作片段：

function Summarise() {
ID = prompt("Enter a Customer ID number ", -1)
var totalowed = 0;
var totalcustomers = 0;
while(ID != -1) 
{
    var gasUsed = 0;
    var total = 0;
    gasUsed = prompt("Enter amount of gas used ", "0");
    ///Standard Rate is used to assist in the calculation of customers in excess of 60 Gas Used
    StandardRate = 60 * 1.75
    if(gasUsed <= 60) 
    {
        total = gasUsed * 2;
        document.write("Customers ID: " + ID);
        document.write(" has gas usage of " + gasUsed);
        document.write(" and owes $" + total);
        document.write("<br/>");
    } 
    else 
    {
        total= (gasUsed - 60) * 1.50 + StandardRate;
        document.write("Customers ID: " + ID);
        document.write(" has gas usage of " + gasUsed);
        document.write(" and owes $" + total);
        document.write("<br/>");
    }
    totalowed = total + totalowed;
    totalcustomers = ++totalcustomers;
    ID = prompt("Enter a Customer ID number ", -1);
}
document.write("Total amount owed $" + totalowed);
document.write("<br/>")
document.write("Total Number of customers:" + totalcustomers);
}
Summarise();

totalowed和totalcustomers是在while循环中声明的，因此在它之外不可用。您需要在while环路之外定义它们。

您没有将提示中的字符串转换为整数。请参阅此处：

您可以使用：

ID = parseInt(prompt("Enter a Customer ID number ", -1), 10);

请记住为parseInt函数提供基数值以确保其完整性。

如何从提示框中获取数值？

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