c# - 打印 ref 变量

Question

我的任务是打印数组中一组数字的平均值和方差，为此我需要引用我所做的 avg 。但我不明白我现在如何打印 avg 是什么。当我运行程序时，我目前正在打印 0。这是我的代码：

    static double varianceValue(ref double avg, params double[] intValues)
    {
        double sum = 0;
        double f = 0;
        double number = 0;
        double sv = 0;
        double variance= 0;

        foreach (int value in intValues)
        {
            sum += value;
        }

        for (int i = 0; i < intValues.Length; i++)
        {
            number = intValues[i];
            avg = sum / intValues.Length;
            f = number - avg;
            sv += Math.Pow(f, 2);

        }
        variance = sv / (intValues.Length - 1);
        return variance;

    }
    static void Main(string[] args)
    {
        double avg = 0;
        Console.WriteLine("The avg of the variables in the array are: {0}", varianceValue(ref avg));
        Console.WriteLine("\nThe variance of 11, 13, 17, 19, 23 is: {0}", varianceValue(ref avg, 11.0, 13.0, 17.0, 19.0, 23.0));
        Console.ReadKey();
    }

Answer 1

此时您正在打印零，因为您调用时数组为空

 Console.WriteLine("The avg of the variables in the array are: {0}", varianceValue(ref avg));

首先调用带有数组参数的方差函数（这也将设置平均值）。然后自己调用 avg 。

static void Main(string[] args)
{
    double avg = 0;
    Console.WriteLine("\nThe variance of 11, 13, 17, 19, 23 is: {0}", varianceValue(ref avg, 11.0, 13.0, 17.0, 19.0, 23.0));
   Console.WriteLine("The avg of the variables in the array are: {0}", avg);
    Console.ReadKey();
}