20145307第二次JAVA学习实验报告

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20145307《Java程序设计》实验报告二：Java面向对象程序设计

实验要求

1.初步掌握单元测试和TDD

2.理解并掌握面向对象三要素：封装、继承、多态

3.初步掌握UML建模

4.熟悉S.O.L.I.D原则

5.了解设计模式

实验内容

一、单元测试

1.三种代码

伪代码：以简洁的自然语言表明设计步骤

百分制转五分制：如果成绩小于60，转成“不及格” 如果成绩在60与70之间，转成“及格” 如果成绩在70与80之间，转成“中等” 如果成绩在80与90之间，转成“良好” 如果成绩在90与100之间，转成“优秀” 其他，转成“错误”

产品代码：用以实现特定功能的程序或机器语言；

    package exp1;

    public class EVER{

   public static String percentage2fivegrade(int grade){

   //如果成绩小于60，转成“不及格”

      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";

  //其他，转成“错误”

  else

       return "错误";

}

}

测试代码：用以对产品代码进行测试的代码

二、复数的四则运算

原设计代码如下：

import java.util.Scanner;

class complex {

double a, b;

complex() {

    this.a = 0;

    this.b = 0;

}

complex(double a) {

    this.a = a;

    this.b = 0;

}

complex(double a, double b) {

    this.a = a;

    this.b = b;

}

complex add(complex p1, complex p2) {

    complex p = new complex(p1.a + p2.a, p1.b + p2.b);

    return p;

}

complex minus(complex p1, complex p2) {

    complex p = new complex(p1.a - p2.a, p1.b - p2.b);

    return p;

}

void print() {

    System.out.println("复数的值为：");

    if (this.b != 0)

        System.out.println(this.a + "+" + this.b + "i");

    else

        System.out.println(this.a);

}

}

public class compleXX {

public static void main(String[] args) {

    System.out.printf("依次输入两组数字每组表示一个复数：");

    Scanner scanner=new Scanner(System.in);

    int q,w,e,r,t;

    q=scanner.nextInt();

    w=scanner.nextInt();

    e=scanner.nextInt();

    r=scanner.nextInt();

    complex c = new complex();

    complex c1 = new complex(q, w);

    complex c2 = new complex(e, r);

    c1.print();

    c2.print();

    System.out.printf("输入1来选择加法运算输入2来选择减法运算");

    t=scanner.nextInt();

    switch (t){

    case (1):

    System.out.println("这两个复数的和为：");

    System.out.println((c.add(c1, c2).a + "+" + c.add(c1, c2).b + "i").toString());

    case (2):

    System.out.println("这两个复数的差为：");

    System.out.println((c.minus(c1, c2).a + "+" + c.minus(c1, c2).b + "i").toString());}

    }

}

修改plan

    public class Complex

{

double real,img;

public Complex()

{

    this.real=0;

    this.img =0;

}

public Complex(double real,double img)

{

    this.real=real;

    this.img =img;

}

public double getReal()

{

    return this.real;

}      

public double getImage()

{

     return this.img;

}

public double getReal(Complex c)

{

    return c.real;

}      

public double getImage(Complex c)

{

    return c.img;

}       

public void setReal    (double real)

{

    this.real=real;

}      

public void setImage(double img)

{

    this.img =img;

}      

public Complex addComplex(Complex a,Complex b)

{

    Complex temp =new Complex();

    temp.real=a.real+b.real;

    temp.img =a.img +b.img;

    return temp;

}

public Complex decComplex(Complex a,Complex b)

{

    Complex temp = new Complex();

    temp.real = a.real - b.real;

    temp.img  = a.img  - b.img;

    return temp;

}

public Complex mulComplex(Complex a,Complex b)

{

    Complex temp = new Complex();

    temp.real = a.real*b.real-a.img*b.img;

    temp.img    = a.real*b.img+a.img*b.real;

    return temp;

}

public Complex divComplex(Complex a,Complex b)

{

    Complex temp = new Complex();

    temp.real=(a.real*b.real+a.img*b.img)/(b.real*b.real+b.img*b.img);

    temp.img =(a.img*b.real-a.real*b.img)/(b.real*b.real+b.img*b.img);

    return temp;

}

public void printComplex()

{

    System.out.println(""+this.real+"+"+this.img+"i");

}       

public String toString()

{

    String fin=" ";

    if(img>0)

    {

        fin = real+"+"+img+"i";

    }

    else if(img<0)

    {

        fin = real+ ""+img+"i";

    }

    else

    {

        fin = fin;

    }

    return  fin;

}

for test：

public static void main(String[] args)

{

    Complex q = new Complex(6, 3);

    q.printComplex();

    Complex w = new Complex(2, 7);

    w.printComplex();

    Complex asd = new Complex();

    asd = asd.addComplex(q, w);

    asd.printComplex();

    asd= asd.decComplex(q, w);

    asd.printComplex();

    asd = asd.mulComplex(q, w);

    asd.printComplex();

    asd = asd.divComplex(q, w);

    asd.printComplex();

}