Question

我正在为学校做一个项目，我试图计算一定距离的汽车油耗，但开关总是返回0.我尝试了不同的东西，但它们似乎都没有工作

    public Double DetermineFuelConsumption (String Car, Double Kilometers)
    {
        Double FuelConsumption = 0;

        switch (Car)
        {
            // (14 / 100) ---> Liters per 100 Kilometers
            case "LaFerrari":
                FuelConsumption = (14 / 100) * Kilometers;
                break;
            case "Nissan GT-R Nismo":
                FuelConsumption = (12 / 100) * Kilometers;
                break;
            case "Pagani Huayra":
                FuelConsumption = (18 / 100) * Kilometers;
                break;
            case "McLaren P1":
                FuelConsumption = (8 / 100) * Kilometers;
                break;
            case "Lamborghini Aventador":
                FuelConsumption = (16 / 100) * Kilometers;
                break;
            case "Smart":
                FuelConsumption = (4 / 100) * Kilometers;
                break;
            case "Porsche 911":
                FuelConsumption = (9 / 100) * Kilometers;
                break;
            case "Audi R8":
                FuelConsumption = (15 / 100) * Kilometers;
                break;
        }
        return FuelConsumption;
    }

Answer 1

您除以100的所有数字都将为0。

这是整数除法：整数除以整数的结果总是整数。您需要指定您的数字是浮点类型：

public Double DetermineFuelConsumption (String Car, Double Kilometers)
{
    Double FuelConsumption = 0;

    switch (Car)
    {
        // (14 / 100) ---> Liters per 100 Kilometers
        case "LaFerrari":
            FuelConsumption = (14d / 100d) * Kilometers;
            break;
        case "Nissan GT-R Nismo":
            FuelConsumption = (12d / 100d) * Kilometers;
            break;
        case "Pagani Huayra":
            FuelConsumption = (18d / 100d) * Kilometers;
            break;
        case "McLaren P1":
            FuelConsumption = (8d / 100d) * Kilometers;
            break;
        case "Lamborghini Aventador":
            FuelConsumption = (16d / 100d) * Kilometers;
            break;
        case "Smart":
            FuelConsumption = (4d / 100d) * Kilometers;
            break;
        case "Porsche 911":
            FuelConsumption = (9d / 100d) * Kilometers;
            break;
        case "Audi R8":
            FuelConsumption = (15d / 100d) * Kilometers;
            break;
    }
    return FuelConsumption;
}

这里，d后缀指定这些数字是双精度数，而不是整数。

Answer 2

试

FuelConsumption = (14d / 100d) * Kilometers;

Answer 3

你试图划分2个整数（a / b），以防 a＆lt; b 将是 0.some-number 的分数，而舍入为int ，这意味着0.然后乘以0 *公里。你看到了这张照片。

改为将其更改为(14 / 100d)。

开关的返回值始终为0

3 个答案: