1!到n!的和

include <iostream>#include <cmath>#include <cstdio>#include <cstdlib>#include <iomanip>using namespace std;int main(){    int n,i,sum,j,b=0,a;    while(cin>>n&&n>=1&&n<=12)    {        sum=0;        for(i=1;i<=n;i++)        {            a=1;            for(j=1;j<=i;j++)            {                a=a*j;            }            sum+=a;        }b++;        if(b>50)            break;        cout<<sum<<endl;    }return 0;}

输出结果：