5.2 5.3测试与封装

程序代码

import java.text.DecimalFormat;

import java.util.Scanner;



public class Zhidao {

	

	public static void main(String[] args) {

		String condition = "";

		Zhidao zhidao = new Zhidao();

		do{

		Scanner scanner = new Scanner(System.in);

		try{

		System.out.print("请输入第一个数：");

		double x = scanner.nextDouble();

		System.out.print("请输入第二个数：");

		double y = scanner.nextDouble();

		System.out.print("请输入运算符：");

		String s = scanner.next();

		char z = s.charAt(0);

		zhidao.yunsuan(x, y, z);

		}catch(Exception e){

			System.out.println("请输入正确的数据！");

		}

		System.out.print("是否继续？continue：继续，任意字符：结束");

		condition = scanner.next();

	

		}while("continue".equals(condition));

	}

	

	public static void yunsuan(double x,double y,Character z){

		DecimalFormat r=new DecimalFormat(); 

		r.applyPattern("#0.00");

		if(z.equals('+')){

			System.out.println(x+"+"+y+"=" + r.format((x+y)));

		} else if(z.equals('-')){

			System.out.println(x+"-"+y+"=" + r.format((x-y)));

		} else if(z.equals('*')){

			System.out.println(x+"*"+y+"=" + r.format((x*y)));

		} else if(z.equals('/')){

			if(y==0){

				System.out.println("被除数不能为0");

			} else{

				System.out.println(x+"/"+y+"=" + r.format((x/y)));

			}

	

		}else{

			System.out.println("无法识别改运算符");

		}

	}



}public int jianfa(int a,int b) throws Error//减法

    {

        if(a>100||b>100||a<-100||b<-100)

        {

            throw new Error("数值范围不能超出-100到100");

        }

        return a*b;

　　

　　

测试代码

import static org.junit.Assert.*;



import org.junit.Test;





public class Test {



    @Test

    public void testTiM() throws Error {

        yunsuan s=new s();

        String result=s.jianfa(3,2);

        assertEquals(1,result);

        

    }



}