小程序-----可以計算任意個數數字的加、乘運算方法實現

public class Text1{
    public static void main(String args[]){
        System.out.println("和等於："+add(2,5));
        System.out.println("和等於："+add(2,5,100,25,23));
        System.out.println("和等於："+add());
        System.out.println("乘等於："+cheng(2,4));
        System.out.println("乘等於："+cheng(2,4,6));
        System.out.println("乘等於："+cheng());
    }
    public static int add(int ... arr){
        int num=0;
        assert arr.length==0;
        for(int lemp:arr){
            num+=lemp;
        }
        return num;
    }
    public static double cheng(double ... arr){
        if(arr.length==0)
        return 0.0;
        double num=1;
        for(double lemp:arr){
            num*=lemp;
        }
        return num;
    }
}