这个题怎么写？大佬们帮帮忙

Question

java计算sum=1-1/2!+1/3!-...(-1)的（n-1）次方1/n!

Answer 1

public class Question
{
    // 计算sum=1-1/2!+1/3!-...(-1)的（n-1）次方1/n!
    public calculate(int n)
    {
        int sign = 1;
        double factorial = 1;
        double sum = 1;
        
        for (int i = 2; i <= n; ++i)
        {
            sign *= -1;
            factorial *= i;
            sum += sign * 1.0 / factorial;
        }
        
        return sum;
    }

}