求一个数学算法,递减,50分

Question

分配数量.一级获得总数的80%,二级获得剩下总数的80%,依次类推...
如:总数100分配从一到多级分配为:
80 16 3.2 ....

Answer 1

private float GetNum(float totalNum, int classNum)
        {
            float currentNum = 0;
            for (int i = 1; i < classNum; ++i)
            {
                currentNum = totalNum * 0.8;
                totalNum = totalNum - currentNum;
            }            return currentNum;
        }

Answer 2

 public Form1()
        {
            double cn = GetNum(100, 2);
            MessageBox.Show(cn.ToString());
            InitializeComponent();
        }        private double GetNum(double totalNum, double classNum)
        {
            double currentNum = 0;
            for (int i = 0; i < classNum; ++i)
            {
                currentNum = totalNum * 0.8;
                totalNum = totalNum - currentNum;
            }            return currentNum;
        }小改了一下，经过验证啦！楼主放心使用

Answer 3

private double GetNum(double totalNum, double classNum)
        {
            return totalNum * Math.Pow(1 - 0.8, classNum - 1) * 0.8;
        }

Answer 4

g(1)=100(n=1)
g(n)=g(n-1)*20%(n>=2)
f(n)=g(n)*80%

Answer 5

g(1)=100(n=1)
g(n)=g(n-1)*20%(n>=2)
f(n)=g(n)*80%