程序代码：

include<iostream>
using namespace std;
#include<cmath>
void main()
{
    int x=1;
    float n=1.0,t=1,sum=0;
    do{
        t=1/n;
        sum+=t;
        n=n*(x++);
    }while((fabs(t))>1e-6);
    cout<<"e="<<sum<<endl;
}

程序代码：

#include <iostream>
using namespace std;

int main( void )
{
    double e = 0;
    for( unsigned i=0,f=1; f<1000000; f*=++i )
        e += 1.0/f;
    cout << "e = " << e << endl;
}