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  • 第一次作业——四则运算

    需求分析

     　　1、控制运算表达式题目数量，控制题目中数值的大小

    　　 2、题目中存在分数形式要进行约分

     　　3、运算符个数不能超过3个

     　　4、不能出现重复题目，即两个运算表达式的计算步骤不能完全相同

     　　5、程序同时支持计算生成的每道题目，并对结果进行约分

    　　 6、对用户所做答案进行判断，并且输出正确答案或错误答案

    功能设计

     　　基本功能 

      　  　　1、根据控制台输入的数字随机生成指定运算元个数和算式数目的运算符

     　　       2、基本的四则运算功能

      　　      3、式子中的分数和最终计算结果均约分到最简

    设计实现

    　　环境

    　　　　windows10+java

    　　程序结构设计

          

    程序设计

    • 功能点1：生成随机数

      随机数生成方法：
    public Num createNum(int range)

    　　

     1 package method;
 2 
 3 import java.util.Random;
 4 import method.Num;
 5 
 6 public class randomNum {
 7     public Num createNum(int range) {
 8         Num num = new Num();
 9         Random rand = new Random();
10         int numerator = rand.nextInt(range + 1);
11         int denominator = rand.nextInt(10) + 1;
12         if (rand.nextInt(1) == 1) {
13             num.setNumerator(numerator);
14             num.setDenominator(1);
15         } else {
16             num.setNumerator(numerator);
17             num.setDenominator(denominator);
18         }
19         num = reduction(num);
20         return num;
21     }
22 
23     public Num reduction(Num num) {
24         int numerator = num.getNumerator();
25         int denominator = num.getDenominator();
26         if (numerator == 0) {
27             num.setDenominator(1);
28             return num;
29         }
30         int divisor = getMaxDivisor(numerator, denominator);
31         if (divisor == 1) {
32             return num;
33         } else {
34             num.setNumerator(num.getNumerator() / divisor);
35             num.setDenominator(num.getDenominator() / divisor);
36             return num;
37         }
38     }
39 
40     public int getMaxDivisor(int numerator, int denominator) {
41         if (denominator == 0) {
42             return numerator;
43         } else {
44             return getMaxDivisor(denominator, numerator % denominator);
45         }
46     }
47 }

    • 功能点2：生成随机运算符

      随机运算符生成方法：
    public String createOperator()
     1 package method;
 2 
 3 import java.util.Random;
 4 
 5 public class randomOperator {
 6     public String createoperator() {
 7         String operator = null;
 8         Random rand = new Random();
 9         int n = rand.nextInt(4);
10         switch (n) {
11         case 0:
12             operator = "+";
13             break;
14         case 1:
15             operator = "-";
16             break;
17         case 2:
18             operator = "*";
19             break;
20         case 3:
21             operator = "÷";
22             break;
23         default:
24             operator = "+";
25             break;
26         }
27         return operator;
28     }
29 }

    • 功能点3：组成算数表达式

      表达式表示：
    类型：ArrayList
组成方法：
    public ArrayList<Object> createArithmetic(int range)

    • 功能点4：计算表达式结果并输出文档

      逆波兰式转换：
    public ArrayList<Object> toRPN(ArrayList<Object> list)
逆波兰式计算
    public Num countRPN(ArrayList<Object> right)
    private Num twoResult(String is, Num op1, Num op2)
      1 package method;
  2 
  3 import java.util.ArrayList;
  4 import java.util.Iterator;
  5 import method.Num;
  6 import method.Stacks;
  7 
  8 public class RPN {
  9     public ArrayList<Object> toRPN(ArrayList<Object> list) {
 10         ArrayList<Object> right = new ArrayList<Object>();// 存储右序表达式
 11         Stacks aStack = new Stacks();// 栈
 12         String operator;
 13         int position = 0;// 当前指针位置
 14         while (true) {
 15             // 当前指针为符号
 16             if (isOperator(list.get(position).toString())) {
 17                 // 栈为空，或指针为（，直接进栈
 18                 if (aStack.top == -1
 19                         || ((String) list.get(position)).equals("(")) {
 20                     aStack.push(list.get(position));
 21                 } else {
 22                     // 指针为）
 23                     if (((String) list.get(position)).equals(")")) {
 24                         // 将栈内（后的运算符出栈
 25                         while (true) {
 26                             if (aStack.top != -1
 27                                     && !((String) aStack.top()).equals("(")) {
 28                                 operator = (String) aStack.pop();
 29                                 right.add(operator);
 30                             } else {
 31                                 if (aStack.top != -1)
 32                                     aStack.pop();
 33                                 break;
 34                             }
 35                         }
 36                     } else {
 37                         while (true) {
 38                             // 栈不为空，判断优先级
 39                             if (aStack.top != -1
 40                                     && priority((String) list.get(position),
 41                                             (String) aStack.top())) {
 42                                 operator = (String) aStack.pop();
 43                                 if (!operator.equals("("))
 44                                     right.add(operator);
 45                             } else {
 46                                 break;
 47                             }
 48 
 49                         }
 50                         aStack.push(list.get(position));
 51                     }
 52                 }
 53             }
 54             // 数字入栈
 55             else {
 56                 right.add(list.get(position));
 57             }
 58             position++;
 59             if (position >= list.size())
 60                 break;
 61         }
 62         // 栈内剩余运算符出栈
 63         while (aStack.top != -1) {
 64             operator = (String) aStack.pop();
 65             if (!operator.equals("("))
 66                 right.add(operator);
 67         }
 68         return right;
 69     }
 70 
 71     // 判断是否为运算符
 72     public static boolean isOperator(String operator) {
 73         if (operator.equals("+") || operator.equals("-")
 74                 || operator.equals("*") || operator.equals("÷")
 75                 || operator.equals("(") || operator.equals(")"))
 76             return true;
 77         else
 78             return false;
 79     }
 80 
 81     // 设置操作符号的优先级别
 82     public static boolean priority(String operatorout, String operatorin) {
 83         int m = 0, n = 0;
 84         String addop[][] = { { "+", "-", "*", "÷", "(", ")" },
 85                 { "+", "-", "*", "÷", "(", ")" } };
 86         int first[][] = { { 1, 1, 2, 2, 2, 0 }, { 1, 1, 2, 2, 2, 0 },
 87                 { 1, 1, 1, 1, 2, 0 }, { 1, 1, 1, 1, 2, 0 },
 88                 { 2, 2, 2, 2, 2, 0 }, { 2, 2, 2, 2, 2, 2 } };
 89         for (int i = 0; i < 6; i++) {
 90             if (operatorin.equalsIgnoreCase(addop[0][i]))
 91                 m = i;
 92         }
 93         for (int i = 0; i < 6; i++) {
 94             if (operatorout.equalsIgnoreCase(addop[1][i]))
 95                 n = i;
 96         }
 97         if (first[m][n] == 1) {
 98             return true;
 99         } else
100             return false;
101     }
102 
103     // 逆波兰式计算
104     public Num countRPN(ArrayList<Object> right) {
105         // 栈
106         Stacks aStack = new Stacks();
107         Num op1, op2, result = null;
108         String is = null;
109         Iterator<Object> it = right.iterator();
110 
111         while (it.hasNext()) {
112             Object ob = it.next();
113             is = ob.toString();
114             if (isOperator(is)) {
115                 op2 = (Num) aStack.pop();
116                 op1 = (Num) aStack.pop();
117                 Num do_0 = twoResult(is, op1, op2);
118                 if (do_0.getDenominator() == 0) {
119                     return (new Num(-1, 1));
120                 }
121                 aStack.push(do_0);
122             } else
123                 aStack.push(ob);
124         }
125         result = (Num) aStack.pop();
126         return result;
127     }
128 
129     // 计算两个数
130     private Num twoResult(String is, Num op1, Num op2) {
131         // 结果数
132         Num result = new Num();
133         randomNum f1 = new randomNum();
134         // 获取分子分母
135         int n1 = op1.getNumerator();
136         int d1 = op1.getDenominator();
137         int n2 = op2.getNumerator();
138         int d2 = op2.getDenominator();
139         // 判断运算符
140         switch (is) {
141         case "+":
142             if (d1 != d2) {
143                 n1 = n1 * d2;
144                 n2 = n2 * d1;
145                 d1 = d1 * d2;
146                 d2 = d1;
147                 result.setNumerator(n1 + n2);
148                 result.setDenominator(d1);
149                 result = f1.reduction(result);
150             } else {
151                 result.setNumerator(n1 + n2);
152                 result.setDenominator(d1);
153                 result = f1.reduction(result);
154             }
155             break;
156         case "-":
157             if (d1 != d2) {
158                 n1 = n1 * d2;
159                 n2 = n2 * d1;
160                 d1 = d1 * d2;
161                 d2 = d1;
162                 result.setNumerator(n1 - n2);
163                 result.setDenominator(d1);
164                 result = f1.reduction(result);
165             } else {
166                 result.setNumerator(n1 - n2);
167                 result.setDenominator(d1);
168                 result = f1.reduction(result);
169             }
170             break;
171         case "*":
172             result.setNumerator(n1 * n2);
173             result.setDenominator(d1 * d2);
174             result = f1.reduction(result);
175             break;
176         case "÷":
177             if (n2 == 0) {
178                 result = new Num(0, 0);
179                 break;
180             }
181             result.setNumerator(n1 * d2);
182             result.setDenominator(d1 * n2);
183             result = f1.reduction(result);
184             break;
185         default:
186             break;
187         }
188         return result;
189     }
190 }
    • 功能点5：比较答案
     1 package method;
 2 
 3 import java.util.ArrayList;
 4 import java.util.Scanner;
 5 
 6 import method.Arithmetic;
 7 import method.RPN;
 8 
 9 public class Main {
10     public static void main(String[] args){
11         Arithmetic arithmetic = new Arithmetic();
12         ArrayList<Object> list = arithmetic.createarithmetic(3);
13         for (int i = 0; i < list.size(); i++) {  
14             System.out.print(list.get(i));  
15         }
16         RPN rpn = new RPN();
17         ArrayList<Object> right = rpn.toRPN(list);
18         Num num = new Num();
19         num = rpn.countRPN(right);
20         String a = num.toString();
21         Scanner answer = new Scanner(System.in);  
22         System.out.println(); 
23         System.out.print("输入答案：");   
24         String name = answer.nextLine(); 
25         if(name.equals(a)){
26             System.out.println("正确 ");
27         }else{
28             System.out.println("错误 ");
29             System.out.print("正确答案：" + a);
30         }
31     }
32 }

    CODING地址：https://coding.net/u/hydralwz/p/size/git

    PSP记录表

    PSP2.1 Personal Software Process Stages Time Senior Student Time
    Planning 计划 10 10
    · Estimate 估计这个任务需要多少时间 10 8
    Development 开发 158 324
    · Analysis 需求分析 (包括学习新技术) 13 7
    · Design Spec 生成设计文档 17 8
    · Design Review 设计复审 5 3
    · Coding Standard 代码规范 10 21
    · Design 具体设计 20 50
    · Coding 具体编码 60 150
    · Code Review 代码复审 10 30
    · Test 测试（自我测试，修改代码，提交修改） 20 20
    Reporting 报告 10 NaN
    · 测试报告 10 NaN
    · 计算工作量 10 NaN
    · 并提出过程改进计划 20 NaN
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  • 原文地址：https://www.cnblogs.com/hydralwz/p/7586651.html
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