20155222 2016-2017-2 《Java程序设计》实验二

• 1 测试

public class MyUtil{
    public static String percentage2fivegrade(int grade){
        //如果成绩小于60，转成“不及格”
        if (grade < 60  && grade >=0)
            return "不及格";
            //如果成绩在60与70之间，转成“及格”
        else if (grade < 70 && grade >=0)
            return "及格";
            //如果成绩在70与80之间，转成“中等”
        else if (grade < 80 && grade >=0)
            return "中等";
            //如果成绩在80与90之间，转成“良好”
        else if (grade < 90 && grade >=0)
            return "良好";
            //如果成绩在90与100之间，转成“优秀”
        else if (grade <= 100 && grade >=0)
            return "优秀";
            //其他，转成“错误”
        else
            return "错误";
    }
}
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));
    }
    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));
    }
    public void testException() {
        assertEquals("错误", MyUtil.percentage2fivegrade(-5));
        assertEquals("错误", MyUtil.percentage2fivegrade(105));
    }
}

• 2 Stringbuffer

public class StringBufferDemo{
   public static void main(String [] args){
                StringBuffer buffer = new StringBuffer();
                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());
        }
}
public class StringBufferDemoTest extends TestCase {
    StringBuffer a = new StringBuffer("StringBuffer");
    StringBuffer b = new StringBuffer("StringBufferStringBuffer");
    StringBuffer c = new StringBuffer("StringBufferStringBufferStringBuffer");
    public void testchatAt() {
        assertEquals('S',a.charAt(0));
        assertEquals('f',b.charAt(20));
        assertEquals('B',c.charAt(30));
    }
    public void testcapacity() {
        assertEquals(28,a.capacity());
        assertEquals(40,b.capacity());
        assertEquals(52,c.capacity());
    }
    public void testindexOf() {
        assertEquals(0,a.indexOf("Str"));
        assertEquals(3,b.indexOf("ing"));
        assertEquals(8,c.indexOf("ffe"));
    }
    public void testlength() {
        assertEquals(12,a.length());
        assertEquals(24,b.length());
        assertEquals(36,c.length());
    }
}

• 3 让系统支持Float类，并在MyDoc类中添加测试代码表明添加正确

abstract class Data {
    abstract public void DisplayValue();
}
class Float extends  Data {
    float value;
    Float() {
        value=100;
    }
    public void DisplayValue(){
        System.out.println (value);
    }
}
// Pattern Classes
abstract class Factory {
    abstract public Data CreateDataObject();
}
class FloatFactory extends Factory {
    public Data CreateDataObject(){
        return new Float();
    }
}
//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 FloatFactory());
        d.DisplayData();
    }
}

• 4 以TDD的方式开发一个复数类Complex

public class Complex {
    private double RealPart;
    private double ImagePart;
    public Complex(double R,double I){
        RealPart = R;
        ImagePart = I;
    }
    double getRealPart(){
        return RealPart;
    }
    double getImagePart(){
        return ImagePart;
    }
    void setRealPart(double R){
        RealPart=R;
    }
    void setImagePart(double I){
        ImagePart=I;
    }
    Complex ComplexAdd(Complex a){
        return new Complex(a.getRealPart()+this.getRealPart(),a.getImagePart()+this.getImagePart());
    }
    Complex ComplexSub(Complex a){
        return new Complex(this.getRealPart()-a.getRealPart(),this.getImagePart()-a.getImagePart());
    }
    Complex ComplexMulti(Complex a){
        return new Complex(this.getRealPart()*a.getRealPart()-this.getImagePart()*a.getImagePart(),this.getRealPart()*a.getImagePart()+this.getImagePart()*a.getRealPart());
    }
    Complex ComplexDiv(Complex a){
        return new Complex((this.getRealPart()*a.getRealPart()+this.getImagePart()*a.getImagePart())/(a.getRealPart()*a.getRealPart()-a.getImagePart()*a.getImagePart()),(this.getImagePart()*a.getRealPart()-this.getRealPart()*a.getImagePart())/(a.getRealPart()*a.getRealPart()-a.getImagePart()*a.getImagePart()));
    }
    @Override
    public String toString(){
        String str="";
        str+=this.getRealPart();
        if(this.getImagePart()>=0) str+="+";
        str+=this.getImagePart();
        str+="i";
        return str;
    }
}
import junit.framework.TestCase;
/**
 * Created by luzijie20155222 on 17-4-21.
 */
public class ComplexTest extends TestCase {
    Complex a=new Complex(1,2);
    Complex b=new Complex(2,1);
    Complex c=new Complex(0,-1);
    Complex d=new Complex(-2,-1);
    public void testGetRealPart() throws Exception {
        assertEquals(1.0,a.getRealPart());
        assertEquals(2.0,b.getRealPart());
        assertEquals(0.0,c.getRealPart());
        assertEquals(-2.0,d.getRealPart());
    }
    public void testGetImagePart() throws Exception {
        assertEquals(2.0,a.getImagePart());
        assertEquals(1.0,b.getImagePart());
        assertEquals(-1.0,c.getImagePart());
        assertEquals(-1.0,d.getImagePart());
    }
    public void testComplexAdd() throws Exception {
        assertEquals("3.0+3.0i",a.ComplexAdd(b).toString());
        assertEquals("2.0+0.0i",b.ComplexAdd(c).toString());
        assertEquals("-2.0-2.0i",c.ComplexAdd(d).toString());
        assertEquals("0.0+0.0i",b.ComplexAdd(d).toString());
    }
    public void testComplexSub() throws Exception {
        assertEquals("-1.0+1.0i",a.ComplexSub(b).toString());
        assertEquals("2.0+2.0i",b.ComplexSub(c).toString());
        assertEquals("2.0+0.0i",c.ComplexSub(d).toString());
        assertEquals("4.0+2.0i",b.ComplexSub(d).toString());
    }
    public void testComplexMulti() throws Exception {
        assertEquals("0.0+5.0i",a.ComplexMulti(b).toString());
        assertEquals("1.0-2.0i",b.ComplexMulti(c).toString());
        assertEquals("-1.0+2.0i",c.ComplexMulti(d).toString());
        assertEquals("-3.0-4.0i",b.ComplexMulti(d).toString());
    }
    public void testComplexDiv() throws Exception {
    }
}

• 5 使用StarUML对实验二中的代码进行建模，发类图的截图，加上学号水印。