20172307 Pair programming project - summary of the first week of four arithmetic operations

20172307 Pair programming project - summary of the first week of four arithmetic operations

paired object

1. Student ID: 20172311
2. Name: Zhao Xiaohai
3. Partner's first week blog address: ( http://www.cnblogs.com/zhaoxiaohai/p/8976043.html )
4. Roles: (1) Driver: Zhao Xiaohai
   (2) Co-pilot: Huang Yutang

demand analysis

• Generate four arithmetic questions, and realize the grading and number of questions.
• Convert infix expressions into postfix expressions, calculate the result of the question, and compare it with the answer entered by the user.
• Realize the operation of true fractions in the operation problem.
• Expansion requirements: To achieve de-duplication of topics.

Design ideas

1.UML class:

2. Ideas

• Generate a class that generates questions, output as a string. Realize the grading of questions, and the number is solved by while and for loops.
• The infix to suffix is ​​realized by referring to the teacher's PPT and using the stack method.
• The realization of the true fraction is realized with reference to the example problem RationalNumber in the book.
• There is no idea of ​​how to de-duplicate the topic.

Related process screenshots

Generate a Fraction of a minimal fractional class:

    public class Fraction {
       int numerator, denominator;

    public Fraction() {
       numerator= (int) (Math.random()*51);
       denominator= (int) (Math.random()*51);
       if(denominator==0)
           denominator=1;
       reduce();
 }

    public void reduce() {
        if (numerator != 0) {
            int common = gcd(Math.abs(numerator), denominator);

            numerator = numerator / common;
            denominator = denominator / common;
        }
    }

    private int gcd(int num1, int num2) {
        while (num1 != num2)
            if (num1 > num2)
                num1 = num1 - num2;
            else
                num2 = num2 - num1;

        return num1;
    }
    public String getFraction()
    {
        String result;
        if(numerator==0)
            result="0";
        else
            if(denominator==1)
                result=numerator+"";
        else
            result=numerator+"/"+denominator;
        return result;
    }
}

2. Generate a Create class to generate the title:

public class Create {
    String[]Arraylist;
    int num,rate;
    public Create(int num ,int rate)
    {
        this.num=num;
        this.rate=rate;
        Arraylist=new String[num];
    }
    public String questionRate(int a)
    {
        String express="";
        String[]OC={"+","-","×","÷"};

        for (int c=0;c<a;c++) {
            Fraction b = new Fraction();
            String d=b.getFraction();
            String e=OC[(int) (Math.random() * 4)];
            while (d=="0"&&e=="÷") {
                Fraction f=new Fraction();
                d = f.getFraction();

            }
            express +=d+" "+e+ " ";
        }

        Fraction c=new Fraction();
        String e=c.getFraction();
        while (express.charAt(4*rate-1)=='÷'&&e=="0")
        {
            Fraction d=new Fraction();
            e=d.getFraction();
        }

        express+=e+" "+"=";
        return express;
    }
    public  void QuestionNum(){
        Create F=new Create(num,rate);
        for(int a=0;a<num;a++)
            Arraylist[a]=F.questionRate(rate);
    }

    public String[] getArraylist() {
        return Arraylist;
    }
    public String getArraylist2(int a)
    {
        String b;
        b=Arraylist[a];
        return b;
    }

    public String toString() {
        String a="";
        for (int b=0;b<num;b++)
            a+=Arraylist[b]+"\n";
        return a;
    }
}

3. Screenshot of the running of the CreatTest class

Difficulties and Solutions

• When running CreateTest, it shows that the array storing the String type is out of bounds
  

Prompt error:

• The solution process
  and pairing partner Zhao Xiaohai read it several times in a row, but still did not see the error. Finally, under the guidance of the class teacher, Mr. Wang, I understood that the problem was when we declared the array. A variable, resulting in an array size of only 1.
  Screenshot of the previous code:
  

Screenshot of the modified code:

Evaluation of twinning partners

In this pairing activity, Xiaohai played the role of the navigator. He completed the idea of ​​the code, and he contributed a lot more than me. I hope I can help him more in the next few weeks of cooperation.

PSP time statistics

PSP2.1	Personal Software Process Stages	Estimated time (minutes)	Actual time (minutes)
Planning	plan	60	70
Estimate	Estimate how long this task will take	30	30
Development	develop	600
Analysis	Requirements analysis (including learning new technologies)	120	180
Coding Standard	Code Specifications (to develop appropriate specifications for current development)	30	20
Design UML	Design project UML class diagram	60	90
Coding	specific code	180
Code Review	code review	180
Test	Testing (self-testing, modifying code, committing changes)	120
Size Measurement	Computational workload (actual time	30
Postmortem & Process Improvement Plan	Post-event summary, and propose a process improvement plan
	total	1410