java实现n个数阶乘之和

publicclassExercise3{publicstaticvoidmain(Stringargs[]){longsum=0,i=1,n=4,item=1,a=1;for(i=1;i=n;i++){do{a=item*a;item++;}while(item=i);sum=sum+a;}System.out.println(sum);}}