Question

我正在处理运费计算器，我已经写好了但我有一点问题。我需要每500英里收取x金额。它可以工作，但如果里程是500的倍数，那么它将再次收取另外500英里的费用。我理解为什么它按照我写的方式来做，但我不知道怎么说750英里才能获得前500英里的其他费用，然后是其他费用。

public static void main(String[] args) {
    JOptionPane.showMessageDialog(null, "This program will ask you to enter the weight\n" +"of your package and how many miles it will travel.\n" +"It will then calculate the shipping cost for you.","Greeting",1);

    String weight = JOptionPane.showInputDialog(null, "Please enter the weight of your package in pounds such as 5.25.", "Weight", 1);
    Double weightnum = Double.parseDouble(weight);
    Double overweight = weightnum-10;

    String miles = JOptionPane.showInputDialog(null, "You have entered " +weightnum +" lbs.\n" +"Please enter in whole numbers how many miles your package needs to travel such as 250.", "Distance", 1);
    int milesnum = Integer.parseInt(miles);
    if (milesnum <500)
    {
        milesnum=0;
    }

    Double cost;
    if (weightnum < 2)
    {
        cost = (milesnum/500+1)*1.10;
    }
    else if (weightnum < 6)
    {
        cost = (milesnum/500+1)*2.50;
    }
    else if (weightnum < 10)
    {
        cost = (milesnum/500+1)*3.90;
    }
    else 
    {
        cost = (milesnum/500+1)*(4.00+(overweight*.5));
    }

    String strcost= String.format("%.2f", cost);

    JOptionPane.showMessageDialog(null, "It will cost $" +strcost +" to ship your " +weightnum +" lbs package " +miles +" miles.\n" +"Have a nice day!", "Cost", 1);
    System.exit(0);
}

}

Answer 1

使用Math.ceil：

返回大于或等于参数且等于数学整数的最小（最接近负无穷大）double值。特殊情况：



如果参数值已经等于数学整数，那么结果与参数相同。



如果参数为NaN或无穷大或正零或负零，则结果与参数相同。



如果参数值小于零但大于-1.0，则结果为负零。

cost = Math.ceil(milesnum/500.0)*multiplier;

表达式milesnum/500.0将返回一个double（而不是milesnum/500，它将返回一个int）。然后math.ceil将该值向上舍入。

如果milesnum == 500，milesnum/500.0为1，则舍入为1.

如果milesnum == 550，milesnum/500.0为1.1，则舍入为2。

Java运费计算器

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