Question

您能否解释一下如何将我的十进制列表格式化为两位小数＆amp;总数应该是100.00？

    static void Main(string[] args)
    {
        string decimalFormat = "0.00";
        decimal[] individuals = { 10, 10, 10 };
        decimal total = 30;
        List<decimal> percents = new List<decimal>();
        foreach (decimal t in individuals)
        {
            decimal percent = (t * 100) / total;
            percents.Add(percent);
        }

        List<decimal> roundToTwoDecimalPercent = new List<decimal>();
        foreach (decimal portfolio in percents)
        {
            roundToTwoDecimalPercent.Add(Math.Round(portfolio, 2));
        }

        decimal percentTotal = decimal.Zero;
        foreach (decimal final in roundToTwoDecimalPercent)
        {
            percentTotal += final;
        }

        Console.WriteLine(percentTotal.ToString(decimalFormat)); // 99.99 but the EXPECTED OUTPUT IS 100.00
        Console.ReadLine();
    }

谢谢， S.Venkatesh

Answer 1

基本上，

四舍五入的总和不一定等于相同数字的四舍五入。

你最后只需要进行一次。

这将为您提供预期的输出：

static void Main(string[] args)
{
    string decimalFormat = "0.00";
    decimal[] individuals = { 10, 10, 10 };
    decimal total = 30;
    List<decimal> percents = new List<decimal>();
    foreach (decimal t in individuals)
    {
        decimal percent = (t * 100) / total;
        percents.Add(percent);
    }

    decimal percentTotal = decimal.Zero;
    foreach (decimal percent in percents)
    {
        percentTotal += percent;
    }

    Console.WriteLine(string.Format("{0:N2}", percentTotal)); 
    Console.ReadLine();
}

OR：如果你是像我一样的LINQ粉丝，这会给你相同的结果：

static void Main(string[] args)
{
    decimal[] individuals = { 10, 10, 10 };

    decimal total = individuals.Sum();

    decimal[] percentages = individuals.Select(i => i * 100 / total).ToArray();

    decimal percentageTotal = percentages.Sum();

    Console.WriteLine(string.Format("{0:N2}", percentageTotal));

    Console.ReadLine();
}

其他示例：使用以下测试应用：

static void Main(string[] args)
{
    decimal[] individuals = { 10, 10, 10 };

    Console.WriteLine("Unrounded figures");

    var percentages = individuals.Select(i => i * 100 / individuals.Sum()).ToList();

    percentages.ForEach(p => Console.WriteLine(p.ToString()));

    decimal percentageTotal = percentages.Sum();
    Console.WriteLine("Their unrounded sum = {0}", percentageTotal);
    Console.WriteLine("Their rounded sum = {0:N2}", percentageTotal);

    Console.WriteLine();
    Console.WriteLine("Rounded figures");

    var roundedPercentages = individuals.Select(i => Math.Round(i * 100 / individuals.Sum(), 2)).ToList();
    roundedPercentages.ForEach(p => Console.WriteLine(p.ToString()));

    decimal roundedPercentageTotal = roundedPercentages.Sum();

    Console.WriteLine("Their unrounded sum = {0}", roundedPercentageTotal);
    Console.WriteLine("Their rounded sum = {0:N2}", roundedPercentageTotal);

    Console.ReadLine();
}

我得到以下输出：

output

如何舍入十进制值列表？

1 个答案: