判断一个分数能不能转化成有限小数

public class Cycle {

    public boolean judge(int up , int down){
        if(down == 0) {      //判断输入，分母不能为0
            System.out.println("input Error");
            return false;
        }

        while(up > down){        //把一个分数化成真分数
            up = up-down;
        }

        for(int i=2 ; i<=up ; i++){             //分子分母约去最大公因子
            if(up%i == 0 && down%i == 0){
                up = up/i;
                down = down/i;
            }
        }

        while(down!=1){             //检查分母是不是只含有2,5两种质因子
            if(down%2 == 0){
                down = down/2;
            }else if(down%5 == 0){
                down = down/5;
            }else{
                return false;
            }
        }
        return true;
    }

    public static void main(String[] args) {
        Cycle c = new Cycle();
        System.out.println(c.judge(10, 15));
    }
}