u Calculate e

 1 #include <iostream>
 2 #include <iomanip>
 3 #include <cstdio>
 4 
 5 using namespace std;
 6 
 7 int factorial(int);
 8 
 9 int main()
10 {
11     int i, n;
12     double e;
13     cout << "n" << " " << "e" << endl;
14     cout << "-" << " " << "-----------" << endl;
15     for(n=0; n<=9; n++) {
16         e = 0;
17         for(i=0; i<=n; i++) {
18             e += 1.0/factorial(i);
19         }
20         if(n < 3) {
21             cout << n << " " << e << endl;
22         }else {
23             cout << fixed << setprecision(9) << n << " " << e << endl;
24         }
25     }
26     return 0;
27 }
28 
29 int factorial(int n) {
30     if(n == 0) {
31         return 1;
32     }else {
33         return n * factorial(n-1);
34     }
35 }