for循环
public class Test{
public static int fac(int n){
int a = 1;
int s = 0;
for(int i =1;i<=n;i++){
a *= i;
s += a;
}
return s;
}
public static void main (String[] args){
int result = fac(3);
System.out.println(result);
}
}
递归
public class Test7{
public static int fac(int n){
if(n == 1){
return 1;
}else{
return fac(n-1)*n;
}
}
public static void main (String[] args){
int result = fac(3);
System.out.println(result);
}
}