java经典问题——求前20项阶乘的和

题目：求1+2!+3!+...+20!的和

public class Practise21 {

	private void getResult(){
		int sum = 0;
		for(int i = 0; i < 20; i ++){
			sum = sum + getNumber(i);
		}
		System.out.println("sum="+sum);
	}
	
	//获得数列的每一项
	private int getNumber(int i){
		if(i == 0){
			return 1;
		}else{
			return getNumber(i - 1)*(i + 1);
		}
	}
	
	public static void main(String[] args) {
		(new Practise21()).getResult();

	}

}public class Prac