Java求阶乘的和,例子是求1!+2!+3!+…+20!的和,阶乘用方法计算
public class Test2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int arg=20;//求1!+2!+3!+...+20!的和
long sum=0;
for(int i=1;i<=arg;i++){
sum+=fact(i);
}
System.out.print(sum);
}
public static long fact(int arg){
long f=1;
for(int i=1;i<=arg;i++){
f*=i;
}
return f;
}
}