u Calculate e

 
   

  
    
#include <iostream>

#include <iomanip>

#include <cassert>

using namespace std;



int factorial(int i)

{

    if(i==0 || i==1)

    {

        return 1;

    }

    else

    {

        int product = 1;

        for(int j=1; j<=i; j++)

        {

            product = product*j;

        }

        return product;

    }

}

int main()

{

    long double sum = 0;

    cout << "n e" << endl;

    cout << "- -----------" << endl;

    for(int n=0; n<10; n++)

    {

        sum = 0;

        for(int i=0; i<=n; i++)

        {

            assert(factorial(i) != 0);

            sum += 1.0/factorial(i);  //1.0 other than 1

        }

        cout.precision(10);

        if (n > 2)

        {

            cout.setf(ios::showpoint);//强制输出相加产生的末尾的0

        }

        cout << n << ' ' << sum;



        cout << endl;



    }

    return 0;

}




 
   

以上是我写的，下面是转来的：

#include<stdio.h>

int main()

{

    int x=2,i=3;

    double sum = 2.5;

    printf("n e\n");

    printf("- -----------\n0 1\n1 2\n2 2.5\n");

    for(i = 3; i != 10; i++){

        x*=i;

        sum+=1.0/(double)x;

        printf("%d %.9f\n",i,sum);

    }

}