Aurora · 发布于 23 小时前 · 浏览 4 回复 0

int n;
cin >> n;
double e = 1.0;
double fac = 1.0;

for(int i = 1; i <= n; i++){
    fac *= i;
    e += 1.0 / fac;
}
printf("%.10lf\n", e);
return 0;