poj1517
简单题
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> using namespace std; double cal(int a) { int temp = 1; double ret = 0; for (int i = 1; i <= a; i++) { temp *= i; ret += 1.0 / temp; } return ret + 1; } int main() { freopen("t.txt", "r", stdin); puts("n e"); puts("- -----------"); puts("0 1"); puts("1 2"); puts("2 2.5"); puts("3 2.666666667"); puts("4 2.708333333"); for (int i = 5; i <= 9; i++) printf("%d %.9f\n", i, cal(i)); return 0; }