for (int i = 1; i <= 50; i++)
{
double mNum = i;
for (int j = i - 1; j > 0; j--)
{
mNum *= j;
}
num += 1 / mNum;
}
Console.WriteLine(num);
第二個：
double num = 0;
int i = 1;
double mNum = 0;
do
{
mNum = i;
for (int j = i - 1; j > 0; j--)
{
mNum *= j;
}
num += 1 / mNum;
i++;
} while (1 / mNum > Math.Pow(10,-4));
Console.WriteLine(num);這個，看不懂誒！要自己計算的，不可以用機器·······