u Calculate e

http://acm.zju.edu.cn/show_problem.php?pid=1113

Time limit: 1 Seconds

Memory limit: 32768K

1. Background

A simple mathematical formula for e is

latex($$e=\sum_{i=0}^n\frac{1}{n!}$$)

where n is allowed to go to infinity. This can actually yield very accurate approximations of e using relatively small values of n.

2. Output

Output the approximations of e generated by the above formula for the values of n from 0 to 9. The beginning of your output should appear similar to that shown below.

3. Sample Output

n e
- -----------
0 1
1 2
2 2.5
3 2.666666667
4 2.708333333

Problem Source: Greater New York 2000

AC的代码:

#include<iostream> using namespace std;

int main() {

• long double t1=6, e=2.5; int n;

cout<<"n"<<" "<<"e"<<endl;

• cout<<"-

"<<endl;

• cout<<0<<" "<<1<<endl; cout<<1<<" "<<2<<endl; cout<<2<<" "<<2.5<<endl;

  • for (n=3;n<10;n++) {

    • e+=1/t1; t1*=(n+1); cout.precision(9); cout.setf(ios::fixed);

    • cout<<n<<" "<<e<<endl;

    } system("pause"); return 0;

}

洪峰