Ying_Lan的博客

1.8 业务的封装 import java.util.*; public class design { public static void main(String[] args) { try { Scanner sc = new Scanner(System.in); //若使用Console, 出错 System.out.println("请输入数字A"); String A = sc.nextLine(); System.out.println("请选择运算符号(.

继承和多态 import java.util.Scanner; class operationFc { String operator; public operationFc(String opt) { operator = opt; } public operation creatOperator(double a, double b) { operation op = null; switch(operator) { case "+" : op = new opera.