2017-2018-2 20165218 Experiment 3 "Agile Development and XP Practice" Experiment Report

Experiment 3 Agile Development and XP Practice

Course: java programming

Name: Zhao Bingyu

Student ID: 20165218

Instructor: Lou Jiapeng

Experiment date: 2018.4.30

Experiment content, steps and experience:

(1) Coding standard

//实验要求
//参考 http://www.cnblogs.com/rocedu/p/6371315.html#SECCODESTANDARD 安装alibaba 插件，解决代码中的规范问题。
//在IDEA中使用工具（Code->Reformate Code）把下面代码重新格式化，再研究一下Code菜单，找出一项让自己感觉最好用的功能。

public class CodeStandard {
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());
if(buffer.capacity()<20)
buffer.append("1234567");
for(int i=0; i<buffer.length();i++)
System.out.println(buffer.charAt(i));
}
}

1. Copy the code into IDEA, use Code->Reformate Codeor shortcut keys Ctrl+Alt+Lto organize

2. Add blank lines according to code logic

3. The red line prompts on lines 15 and 17 are due to the installation of the alibaba plug-in, and it is detected that the code does not conform to the "Alibaba Java Development Manual", and you can change it according to the prompts.

code menu	Function
Override Methods	Overriding methods of base classes
Implement Methods	The method that completes the interface of the current class implements (or the abstract base class)
Generate	Create getter and setter methods for any field in the class
Code->Comment with Line Comment	rewrite this line as a comment
Reformat Code	Indent code in standard format

---

(2) Pair programming

• partner code

public class Complex {

    // 定义属性并生成getter,setter
    private double RealPart;
    private double ImagePart;

    // 定义构造函数
    public Complex() {

    }

    public Complex(double R, double I) {
        this.RealPart = R;
        this.ImagePart = I;
    }

    public double getRealPart() {
        return RealPart;
    }

    public void setRealPart(double realPart) {
        RealPart = realPart;
    }

    public double getImagePart() {
        return ImagePart;
    }

    public void setImagePart(double imagePart) {
        ImagePart = imagePart;
    }

    //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) {
        return new Complex(RealPart + a.RealPart, ImagePart + a.ImagePart);
    }

    Complex ComplexSub(Complex a) {
        return new Complex(RealPart - a.RealPart, ImagePart - a.ImagePart);
    }

    Complex ComplexMulti(Complex a) {
        return new Complex(RealPart * a.RealPart - ImagePart * a.ImagePart, ImagePart * a.RealPart + RealPart * a.ImagePart);
    }

    Complex ComplexDiv(Complex a) {
        Complex d = new Complex();
        d.RealPart = (this.RealPart * a.RealPart + this.ImagePart * a.ImagePart) / (a.RealPart * a.RealPart + a.ImagePart * a.ImagePart);
        d.ImagePart = (this.ImagePart * a.RealPart - this.RealPart * a.ImagePart) / (a.RealPart * a.RealPart + a.ImagePart * a.ImagePart);
        return d;

    }
}

• test code

/**
 * Created by zby on 2018/4/16.
 */

import org.junit.*;

import static org.junit.Assert.*;

public class ComplexTest {
    Complex a = new Complex(1, 2);
    Complex b = new Complex(1, -4);

    @Test
    public void testAdd() {
        assertEquals("2.0 -2.0i", a.ComplexAdd(b).toString());
        System.out.println(a.ComplexAdd(b));
    }

    @Test
    public void testSub() {
        assertEquals("0.0+6.0i", a.ComplexSub(b).toString());
        System.out.println(a.ComplexSub(b));
    }

    @Test
    public void testMulti() {
        assertEquals("9.0 -2.0i", a.ComplexMulti(b).toString());
        System.out.println(a.ComplexMulti(b));
    }

    @Test
    public void testDiv() {
        assertEquals("-0.4117647058823529+0.35294117647058826i", a.ComplexDiv(b).toString());
        System.out.println(a.ComplexDiv(b));
    }
}

• operation result
  

---

(3) Refactoring

• Partner code: I chose the practice questions in partner experiment 1 to realize the number of permutations

import java.util.*;
public class Pnm {
    static Scanner in=new Scanner(System.in);
    public static void main(String args[]) {
    System.out.println("请输入n：");
    int n = in.nextInt();
    System.out.println("请输入m：");
    int m=in.nextInt();
    count(n,m);
    }
    public static void count(int n,int m){
        if(n<m||n<0||m<=0){
            System.out.println("输入错误，请重新输入");
            System.out.println("确保0<m<=n");
            return ;
        }
        int result=1;
        for (int i=0;i<m;i++){
            result*=n;
            n--;
        }
        System.out.println("Pnm="+result);
    }
}

• after refactoring

import java.util.*;

public class PermutNum {
    static Scanner input = new Scanner(System.in);

    public static void main(String args[]) {
        System.out.println("请输入n：");
        int n = input.nextInt();
        System.out.println("请输入m：");
        int m = input.nextInt();
        count(n, m);
    }

    public static void count(int n, int m) {
        if (n < m || n < 0 || m <= 0) {
            System.out.println("输入错误，请重新输入");
            System.out.println("确保0<m<=n");
            return;
        }
        int result = 1;
        for (int i = 0; i < m; i++) {
            result *= n;
            n--;
        }
        System.out.println("PermutNum=" + result);
    }
}

1. Change the class name to PermutNumreflect the function of permutation numbers
2. Define the input object to change toinput

---

(3) Implementing the Caesar cipher

 /**
 * Created by zby on 2018/4/2.
 */

import java.util.*;
import java.lang.*;

public class CaeserCipher {//凯撒密码
    public static void main(String[] args) {
        System.out.println("输入一串字符串作为明文（回车结束）：");
        Scanner input = new Scanner(System.in);
        String m = input.next();//读入一行字符串，以回车为标志
        Arithmetic output = new Arithmetic();
        String c = output.encrpty(m);
        System.out.println("加密后的密文为：" + c);
        System.out.println("解密后的明文为：" + output.decrypt(c));
    }
}

The class of the algorithm method

/**
 * Created by zby on 2018/4/2.
 */

import java.lang.*;

public class Arithmetic {//加密和解密算法
    public String encrpty(String m) {
        StringBuilder result = new StringBuilder();
        char[] mi = m.toCharArray();
        int n = mi.length;
        for (int c : mi) {
            if (c >= 'a' && c <= 'z') {
                c += 3; // 移动key%26位
                if (c < 'a')
                    c += 26; // 向左超界
                if (c > 'z')
                    c -= 26; // 向右超界
            }
            // 如果字符串中的某个字符是大写字母
            else if (c >= 'A' && c <= 'Z') {
                c += 3; // 移动key%26位
                if (c < 'A')
                    c += 26;// 同上
                if (c > 'Z')
                    c -= 26;// 同上
            }
            result.append((char) c);
        }
        return result.toString();
    }

    public String decrypt(String m) {
        StringBuilder result = new StringBuilder();
        char[] mi = m.toCharArray();
        int n = mi.length;
        for (int c : mi) {
            if (c >= 'a' && c <= 'z') {
                c -= 3; // 向前移动3位
                if (c < 'a')
                    c += 26; // 向左超界
                if (c > 'z')
                    c -= 26; // 向右超界
            }
            // 如果字符串中的某个字符是大写字母
            else if (c >= 'A' && c <= 'Z') {
                c -= 3; // 向前移动3位
                if (c < 'A')
                    c += 26;// 同上
                if (c > 'Z')
                    c -= 26;// 同上
            }
            result.append((char) c);
        }
        return result.toString();
    }

}

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References

1. A preliminary study of refactoring and Intellij Idea