Question

例如70105-计算符合参数年龄范围的任何出生日期

    CalculateDob(int youngestAge, int oldestAge)
     {

        Random r = new Random();
        int age = 0;
        age = r.Next(70, 105);

        var year = DateTime.Now.Year - age;
        var month = r.Next(1, 12);
        var day = r.Next(1, 28);
        return new DateTime(year, month, day); 
    }

我当前的解决方案几乎可以工作，但是在某些极端情况下会失败，即在某些情况下由于我认为是一个月的问题而返回69。

有什么建议吗？

Answer 1

您之所以会达到69岁，是因为如果CalculateDob返回的月份是当前月份(DateTime.Now)之后的月份；到那时Dob仍达不到70年。另外，您应该从方法中带出随机构造函数，并将其设为静态，以免在每次调用时都保持rand生成器的种子状态。

public static void Main(string[] args)
{
    for (int i = 0; i < 100; i++)
    {
        var birthDate = CalculateDob(70, 105);
        var now = DateTime.Now;
        int age = now.Year - birthDate.Year;
        if (now.Month < birthDate.Month || (now.Month == birthDate.Month && now.Day < birthDate.Day))
        {
            age--;
        }
        Console.WriteLine(age);                
    }
}

//Construct this as static so that we don't keep seeding the rand    
private static readonly Random _random = new Random();

static DateTime CalculateDob(int youngestAge, int oldestAge)
{


    int age = 0;
    age = _random.Next(70, 105);
    var today = DateTime.Now;
    var year = today.Year - age;
    var month = _random.Next(1, 12);

    //Age might less than youngest age,
    //if born at/after current month, edge condition
    if (month >= today.Month)
    {

        month = today.Month - 1;
        if (month < 1)
        {
            year--;
            month = 12;
        }
    }

    var day = _random.Next(1, DateTime.DaysInMonth(year, month));
    return new DateTime(year, month, day);
}

按年龄范围计算出生日期

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