First, the needs analysis:

For the preparation of a primary computing applet four operations, program parameters can be customized, and the generated equation result.txt stored in the external file.

Second, the functional implementation:

·basic skills

(1) automatically generates four arithmetic operation of Equation 2 number less than 10 100 (+ - * /), operation results are required within 100

(2) discarding duplicates equation. = 2 + 3 + 3 = 2 and Equation 2 is repeated and 3 + = 3 + 2 = not repeated formula

Number (3) title can be customized

(4) parameters can be controlled

Whether to include multiplication and division

Controllable range values of the operands (e.g., operands within 100 or within 1000)

Whether operands containing negative　　　　

(5) generating operation to an external file title stored in result.txt

· Expansion capabilities

(1) the output of the equation were optimized: by giving all negative operand in parentheses is added, greatly improves the cleanliness of the equation, the equation enhance readability.

Third, the design and implementation:

(1) using rand.nextInt () statements and (int) (Math.random () * number); statement to achieve for generating random numbers

int     A = rand.nextInt (100); // randomly generated integer in the range of 0-100 
int     B = rand.nextInt (100); // randomly generated integer in the range 0-100

Asum[i]=(int) (Math.random()*number1);
Bsum[i]=(int) (Math.random()*number1);

(2) The four operators stored in an array of char, using (int) (Math.random () * number) statement generates four random expression;

char Opera [] = { '+', '-', '*', '/'}; // Opera [0] ~ Opera [. 3] are sequentially output "+", "-", "*", "/ " 
int R & lt = ( int ) (Math.random () * number3); // Analyzing OUT +, -, *, /

(3) using the PrintStream sun = new PrintStream ( "d: /result.txt"); statement stored in the generated equations result.txt document;

PrintStream ps = new PrintStream("d:/result.txt");
System.setOut(ps);

(4) using the int number1 = reader.nextInt (); the number of items to achieve controllable;

System.out.println ( "Enter the number of equations" );
         int number2 = reader.nextInt ();
         int Bsum [] = new new  int [number2];

(5) to achieve a controllable range of values of the operands;

System.out.println ( "number of input control range" );
         int number1 = reader.nextInt ();
         int ASUM [] = new new  int [number1];

( 6) to achieve a negative value calculation;

char Opera2 [] = { '', '-'}; // Opera [0] ~ Opera [. 1] are sequentially output "(space)", "-" 
int n-= ( int ) (Math.random () * number4 ); // The first value is negative if 
int m = ( int ) (Math.random () * number4); // second whether the value is negative

(7) to achieve all negative values in brackets;

char Opera3 [] = { '', '(', ')'}; // Opera [0] ~ Opera [2] sequentially outputs "(space)", "(", ")" 
int R & lt = ( int ) (Math.random () * number3); // Analyzing OUT +, -, *, /

(8) In addition to re-implement the equation operation;

Asum[0]=(int) (Math.random()*number1);
            Bsum[0]=(int) (Math.random()*number2);
        for(int i=1;i<number2;) {
            Asum[i]=(int) (Math.random()*number1);
            Bsum[i]=(int) (Math.random()*number1);
            if(Asum[i]!=Asum[i-1]) {
                i++;
            }
        }

Fourth, the test run:

(1) basic needs test run

(2) development needs test run

Five more satisfied snippet:

char Opera[]= {'+','-','*','/'};//Opera[0]~Opera[3]依次输出“+”，“-”，“*”，“/”
char Opera2[]= {' ','-'};//Opera[0]~Opera[1]依次输出“ （空格）”，“-”
char Opera3[]= {' ','(',')'};//Opera[0]~Opera[2]依次输出“ （空格）”，“（”，“）”

 

for(int i=0;i<number2;i++) {
int n=(int) (Math.random()*number4);//第一个数值是否为负数
int m=(int) (Math.random()*number4);//第二个数值是否为负数
int r=(int) (Math.random()*number3);//判断输出+，-，*，/

System.setOut(ps);
System.out.printf("%c%c%d%c%c%c%c%d%c=\r",Opera3[n*1],Opera2[n],Asum[i],Opera3[n*2],Opera[r],Opera3[m*1],Opera2[m],Bsum[i],Opera3[m*2]);
System.out.println();
}

六、总结：

对新技术的学习能力还需要加强。把所有的方法和对象都放到了一个类中进行了实现，代码的结构层次不明显。

七、PSP

PSP2.1	任务内容	计划共完成需要的时间(h)	实际完成需要的时间(h)
Planning	计划	0.5	1
· Estimate	· 估计这个任务需要多少时间，并规划大致工作步骤	18.3	27.4
Development	开发	5	8
·· Analysis	需求分析 (包括学习新技术)	3	5
· Design Spec	· 生成设计文档	0.5	0.6
· Design Review	· 设计复审 (和同事审核设计文档)	0.5	0.5
· Coding Standard	代码规范 (为目前的开发制定合适的规范)	0.2	0.4
· Design	具体设计	2	2
· Coding	具体编码	2	2
· Code Review	· 代码复审	1	1.5
· Test	· 测试（自我测试，修改代码，提交修改）	3	6
Reporting	报告	0.5	0.5
·· Test Report	· 测试报告	0.2	0.2
· Size Measurement	计算工作量	0.2	0.2
· Postmortem & Process Improvement Plan	· 事后总结 ,并提出过程改进计划	0.5	0.5

20194641-- automatically generates four arithmetic test report