利用for 与switch
package cn.tedu.review;import java.util.Scanner;public class TestMethod {public static void main(String[] args) {for(;;) {System.out.println("请你输入要计算的第一个数字");double number1=new Scanner(System.in).nextDouble();System.out.println("请你输入运算符号：支持+—*/");String key=new Scanner(System.in).nextLine();System.out.println("请你输入要计算的第二个数字");double number2=new Scanner(System.in).nextDouble();switch (key) {case "+": f1(number1,number2); break;case "-": f2(number1,number2); break;case "*": f3(number1,number2); break;case "/": f4(number1,number2); break;default:System.out.println("请重新输入");break;}} }private static void f4(double number1, double number2) {System.out.println(number1+"/"+number2+"="+(number1/number2));}private static void f3(double number1, double number2) {System.out.println(number1+"*"+number2+"="+(number1*number2));}private static void f2(double number1, double number2) {System.out.println(number1+"-"+number2+"="+(number1-number2));}private static void f1(double number1, double number2) {System.out.println(number1+"+"+number2+"="+(number1+number2));}}
