20192321 2020-2021-1 《数据结构与面向对象程序设计》实验三报告
20192321 2020-2021-1 《数据结构与面向对象程序设计》实验三报告
课程:《程序设计与数据结构》
班级:1923
姓名:李锦程
学号:20192321
实验教师:王志强
实验日期:2020年10月8日
必修/选修:必修
实验内容
下载安装并使用IDEA,完成下面实验。
- 初步掌握单元测试和TDD
- 理解并掌握面向对象三要素:封装、继承、多态
- 初步掌握UML建模
- 完成蓝墨云上 (1)-(5)实验。
实验过程及结果
1.Myutil及MyutilTest的编写
产品代码
public class MyUtil {
public static String percentage2fivegrade(int grade){
//如果成绩小于0,转成“错误”
if ((grade < 0))
return "错误";
//如果成绩小于60,转成“不及格”
else if (grade < 60)
return "不及格";
//如果成绩在60与70之间,转成“及格”
else if (grade < 70)
return "及格";
//如果成绩在70与80之间,转成“中等”
else if (grade < 80)
return "中等";
//如果成绩在80与90之间,转成“良好”
else if (grade < 90)
return "良好";
//如果成绩在90与100之间,转成“优秀”
else if (grade <= 100)
return "优秀";
//如果成绩大于100,转成“错误”
else
return "错误";
}
}
测试代码
import org.junit.Test;
import junit.framework.TestCase;
public class MyUtilTest extends TestCase {
@Test
public void testNormal() {
assertEquals("不及格", MyUtil.percentage2fivegrade(55));
assertEquals("及格", MyUtil.percentage2fivegrade(65));
assertEquals("中等", MyUtil.percentage2fivegrade(75));
assertEquals("良好", MyUtil.percentage2fivegrade(85));
assertEquals("优秀", MyUtil.percentage2fivegrade(95));
}
@Test
public void testExceptions() {
assertEquals("错误", MyUtil.percentage2fivegrade(-55));
assertEquals("错误", MyUtil.percentage2fivegrade(105));
}
@Test
public void testBoundary() {
assertEquals("不及格", MyUtil.percentage2fivegrade(0));
assertEquals("及格", MyUtil.percentage2fivegrade(60));
assertEquals("中等", MyUtil.percentage2fivegrade(70));
assertEquals("良好", MyUtil.percentage2fivegrade(80));
assertEquals("优秀", MyUtil.percentage2fivegrade(90));
assertEquals("优秀", MyUtil.percentage2fivegrade(100));
}
}
运行结果截图
2.StringBuffer及StringBufferTest的编写
产品代码
public class StringBufferDemo {
public static void main(String [] args){
StringBuffer buffer = new StringBuffer(20);
buffer.append('S');
buffer.append("tringBuffer");
System.out.println(buffer.charAt(1));
System.out.println(buffer.capacity());
System.out.println(buffer.indexOf("tring"));
System.out.println("buffer = " + buffer.toString());
System.out.println(buffer.length());
}
}
测试代码
import org.junit.Test;
import junit.framework.TestCase;
public class StringBufferDemoTest extends TestCase {
StringBuffer a = new StringBuffer("StringBuffer");
StringBuffer b = new StringBuffer("StringBufferStringBuffer");
StringBuffer c = new StringBuffer("StringBufferStringBufferStringBuffer");
@Test
public void testcharAt() throws Exception {
assertEquals('t', a.charAt(1));
assertEquals('g', a.charAt(5));
assertEquals('r', a.charAt(11));
}
@Test
public void testcapacity() throws Exception {
assertEquals(28, a.capacity());
assertEquals(40, b.capacity());
assertEquals(52, c.capacity());
}
@Test
public void testlength() throws Exception {
assertEquals(12, a.length());
assertEquals(24, b.length());
assertEquals(36, c.length());
}
@Test
public void testindexOf() throws Exception {
assertEquals(0, a.indexOf("Str"));
assertEquals(5, b.indexOf("gBu"));
assertEquals(8, c.indexOf("ffer"));
}
}
运行结果截图
3.OCP原则和DIP原则的应用
abstract class Data {
abstract public void DisplayValue();
}
class Integer extends Data {
int value;
Integer() {
value=21%6;
}
public void DisplayValue(){
System.out.println (value);
}
}
class Long extends Data {
long value;
Long() {
value=20192321;
}
public void DisplayValue(){
System.out.println (value);
}
}
// Pattern Classes
abstract class Factory {
abstract public Data CreateDataObject();
}
class IntFactory extends Factory {
public Data CreateDataObject(){
return new Integer();
}
}
class LongFactory extends Factory {
public Data CreateDataObject(){
return new Long();
}
}
//Client classes
class Document {
Data pd;
Document(Factory pf){
pd = pf.CreateDataObject();
}
public void DisplayData(){
pd.DisplayValue();
}
}
//Test class
public class MyDoc {
static Document d;
public static void main(String[] args) {
d = new Document(new IntFactory());
d.DisplayData();
d = new Document(new LongFactory());
d.DisplayData();
}
}
运行结果截图
4.以TDD的方式开发一个复数类Complex
产品代码
public class Complex {
// 定义属性并生成getter,setter
double RealPart;
double ImagePart;
// 定义构造函数
public Complex(){
RealPart = 0;
ImagePart = 1;
}
public Complex(double R,double I){
ImagePart = I;
RealPart = R;
}
//Override Object
public boolean equals(Object obj){
if(this == obj) {
return true;
}
if(!(obj instanceof Complex)) {
return false;
}
Complex complex = (Complex) obj;
if(complex.RealPart != ((Complex) obj).RealPart) {
return false;
}
if(complex.ImagePart != ((Complex) obj).ImagePart) {
return false;
}
return true;
}
public String toString() {
String string = "";
if (ImagePart > 0)
string = RealPart + "+" + ImagePart + "i";
if (ImagePart == 0)
string = RealPart + "";
if (ImagePart < 0)
string = RealPart + " " + ImagePart + "i";
return string;
}
// 定义公有方法:加减乘除
Complex ComplexAdd(Complex a) {
double b=0,c=0;
b = RealPart+a.RealPart;
c = ImagePart+a.ImagePart;
System.out.println("("+RealPart+"+"+ImagePart+"i) + ("+a.RealPart+"+"+a.ImagePart+") = "+b+"+"+c+"i");
return new Complex(b,c);
}
Complex ComplexSub(Complex a) {
double b=0,c=0;
b = RealPart-a.RealPart;
c = ImagePart-a.ImagePart;
System.out.println("("+RealPart+"+"+ImagePart+"i) - ("+a.RealPart+"+"+a.ImagePart+") = "+b+"+"+c+"i");
return new Complex(b,c);
}
Complex ComplexMulti(Complex a) {
double b=0,c=0;
b = RealPart*a.RealPart;
c = ImagePart*a.ImagePart;
System.out.println("("+RealPart+"+"+ImagePart+"i) * ("+a.RealPart+"+"+a.ImagePart+") = "+b+"+"+c+"i");
return new Complex(b,c);
}
Complex ComplexDiv(Complex a) {
if(a.RealPart==0||a.ImagePart==0) {
System.out.println("被除数不能为0,错误");
return new Complex();
}
double d = Math.sqrt(a.RealPart*a.RealPart)+Math.sqrt(a.ImagePart*a.ImagePart);
double b=0,c=0;
b = (RealPart*a.RealPart+ImagePart*a.ImagePart)/d;
c = Math.round((RealPart*a.ImagePart-ImagePart*a.RealPart)/d);
System.out.println("("+RealPart+"+"+ImagePart+"i) / ("+a.RealPart+"+"+a.ImagePart+") = "+b+"+"+c+"i");
return new Complex(b,c);
}
}
测试代码
import org.junit.Test;
import junit.framework.TestCase;
public class ComplexTest extends TestCase {
Complex complex = new Complex(1, 1);
@Test
public void testAdd() {
assertEquals(new Complex(3.0, 3.0), complex.ComplexAdd(new Complex(2.0, 2.0)));
}
@Test
public void testSub() {
assertEquals(new Complex(-5.0, -2.0), complex.ComplexSub(new Complex(6.0, 3.0)));
}
@Test
public void testMulti() {
assertEquals(new Complex(3.0, 2.0), complex.ComplexMulti(new Complex(3.0, 2.0)));
}
@Test
public void testDiv() {
assertEquals(new Complex(1.0, 1.0), complex.ComplexDiv(new Complex(1.0, 1.0)));
assertEquals(new Complex(0.0, 0.0), complex.ComplexDiv(new Complex(1.0, 0.0)));
//边缘测试
}
}
运行结果截图
5.UML建模
实验过程中遇到的问题和解决过程
- 问题1:在编写测试代码时,@Test报错
- 问题1解决方案:点击旁边的小灯泡依据提示自动导入junit.jar包
- 问题2:找不到jar包
- 问题2解决方案:按照教程在电脑中搜索“junit.jar”,没有找到,通过查询其他博客得知,可以直接在IDEA安装文件夹lib中选择,应选择“junit-4.12.jar”,“junit.jar”没有用
- 问题3:junit不能正常使用
- 问题3解决方案:通过导入库来解决
心得体会
在这次实验过程中,我遇到了许多问题,其中既有知识上的漏洞,也有不细心导致的马虎。在不断修复问题的过程中,我使用了很多方式去查询资料,例如:《数据结构与面向对象程序设计》,博客园平台,CSDN平台,码云平台,知乎app,等。在这个过程中,我还进一步熟悉了Intellij IDEA这个平台的使用与运行方式,提高了自己自主学习的能力,为我接下来学习数据结构以及JAVA语言程序设计打下了坚实的基础。
参考资料
- 《Java程序设计与数据结构教程(第二版)》
- 《Java程序设计与数据结构教程(第二版)》学习指导