题目链接：http://www.cnblogs.com/HQL0301/p/7502315.htm
源码连接：https://gitee.com/a1234321/four_operations/tree/master
一.需求分析
?可以根据输入的题数和数值范围自动生成四则运算表达式。
?表达式包括“+ - * /”这四种运算符。
?可以进行分数的运算，如果题目中出现假分数，则转换成真分数。
?对题目答案进行批改对错，给出正确率。
二.功能设计
(1)基本功能
1.输入参数n，程序生成 n道四则运算题目.
2.用参数来控制生成的四则运算的数值范围.
3.用户可以对相应的题目进行做答.
4.对用户的答案进行判断对错，并给出正确率.
（2）扩展功能
1.查重复，不出现重复的题目（没有实现）
2.对假分数转换成带分数表示
（3）高级功能
1.用户回答正确可以获得相应的积分，错误会扣除相应的积分，积分可以兑换一定的礼品。(后续完善的时候再实现)
三.设计实现
使用java实现，基于控制台。根据所输入的长度，随机生成四则运算题目。
timu包是实现出题
calculate包是题目的做题业务实现
四.代码说明
1 public class calculate<optStack> {
2 private Map<String, Map<String, String>> priorityMap = new HashMap<String, Map<String, String>>();
3 private Stack<String> optStack = new Stack<String>();
4 private Stack<Double> numStack = new Stack<Double>();
5
6 public double calcualte1(String exp) {
7 StringTokenizer vn = new StringTokenizer(exp);
8 while (vn.hasMoreTokens()) {
9 String token = vn.nextToken();
10 transversion(token);
11 }
12 return numStack.pop();
13 }
14 public double calcualte(String exp) {
15 char[] strExp = exp.toCharArray();
16 for(char a: strExp){
17 transversion(""+a+"");
18 }
19 return numStack.pop();
20 }
21
22 private void transversion(String token) {
23 while (false == "=".equals(optStack.peek()) || false == token.equals("=")) {
24 if (true == judgenum(token)) {
25 numStack.push(Double.parseDouble(token));
26 break;
27
28 } else {
29 String priority = priority(optStack.peek(), token);
30 if ("<".equals(priority)) {
31 optStack.push(token);
32 break;
33 } else if ("=".equals(priority)) {
34 optStack.pop();
35 break;
36 } else {
37 double res = calculate(optStack.pop(), numStack.pop(), numStack.pop());
38 numStack.push(res);
39 }
40 }
41 }
42 }
43
44 private double calculate(String opt, double a1, double a2) {
45 if ("+".equals(opt)) {
46 return a2 + a1;
47 } else if ("-".equals(opt)) {
48 return a2 - a1;
49 } else if ("*".equals(opt)) {
50 return a2 * a1;
51 } else if ("/".equals(opt)) {
52 return a2 / a1;
53 } else {
54 throw new RuntimeException("unsupported operator:" + opt);
55 }
56 }
57
58 private boolean judgenum(String token) {
59 int LEN = token.length();
60 for (int ix = 0 ; ix < LEN ; ++ix) {
61 char ch = token.charAt(ix);
62 if (ch == ‘.‘) {
63 continue;
64 }
65 if (false == judgenum(ch)) {
66 return false;
67 }
68 }
69 return true;
70 }
71
72 private boolean judgenum(char ch) {
73 if (ch >= ‘0‘ && ch <= ‘9‘) {
74 return true;
75 }
76 return false;
77 }
78
79 public String priority(String op1, String op2) {
80 return priorityMap.get(op1).get(op2);
81 }
82
83 public calculate() {
84
85 optStack.push("=");
86 Map<String, String> subMap = new HashMap<String, String>();
87 subMap.put("+", ">");
88 subMap.put("-", ">");
89 subMap.put("*", "<");
90 subMap.put("/", "<");
91 subMap.put("(", "<");
92 subMap.put(")", ">");
93 subMap.put("=", ">");
94 priorityMap.put("+", subMap);
95 // -
96 subMap = new HashMap<String, String>();
97 subMap.put("+", ">");
98 subMap.put("-", ">");
99 subMap.put("*", "<");
100 subMap.put("/", "<");
101 subMap.put("(", "<");
102 subMap.put(")", ">");
103 subMap.put("=", ">");
104 priorityMap.put("-", subMap);
105 // *
106 subMap = new HashMap<String, String>();
107 subMap.put("+", ">");
108 subMap.put("-", ">");
109 subMap.put("*", ">");
110 subMap.put("/", ">");
111 subMap.put("(", "<");
112 subMap.put(")", ">");
113 subMap.put("=", ">");
114 priorityMap.put("*", subMap);
115 // /
116 subMap = new HashMap<String, String>();
117 subMap.put("+", ">");
118 subMap.put("-", ">");
119 subMap.put("*", ">");
120 subMap.put("/", ">");
121 subMap.put("(", "<");
122 subMap.put(")", ">");
123 subMap.put("=", ">");
124 priorityMap.put("/", subMap);
125 // (
126 subMap = new HashMap<String, String>();
127 subMap.put("+", "<");
128 subMap.put("-", "<");
129 subMap.put("*", "<");
130 subMap.put("/", "<");
131 subMap.put("(", "<");
132 subMap.put(")", "=");
133 //subMap.put("#", ">");
134 priorityMap.put("(", subMap);
135 // )
136 subMap = new HashMap<String, String>();
137 subMap.put("+", ">");
138 subMap.put("-", ">");
139 subMap.put("*", ">");
140 subMap.put("/", ">");
141 //subMap.put("(", "<");
142 subMap.put(")", ">");
143 subMap.put("=", ">");
144 priorityMap.put(")", subMap);
145 // #
146 subMap = new HashMap<String, String>();
147 subMap.put("+", "<");
148 subMap.put("-", "<");
149 subMap.put("*", "<");
150 subMap.put("/", "<");
151 subMap.put("(", "<");
152 //subMap.put(")", ">");
153 subMap.put("=", "=");
154 priorityMap.put("=", subMap);
155 }
156 }
出题包：
public void generate(int n, int range) {
char[] symbol = { ‘+‘, ‘-‘, ‘*‘, ‘/‘, ‘(‘ };
int op; // 操作数
try {
File writename = new File("D:\\test1.txt");
BufferedWriter out = new BufferedWriter(new FileWriter(writename));
for (int i = 0; i < n; i++) {
String eHead = "" + (i + 1) + ". ";
String e ="";
int exlength = (int) (Math.random() * 4 + 2);
int lbracket = 0;
int rbracket = 0;
int[] whe = new int[exlength];
for (int j = 0; j < exlength; j++) {
char s = symbol[(int) (Math.random() * 5)];
if (j == exlength - 1 && s == ‘(‘) {
int count1 = lbracket;
if (lbracket == 0) {
e += "" + (int) (Math.random() * range) + "";
} else {
e += "" + (int) (Math.random() * range) + "";
for (int q = 0; q < count1; q++) {
e += ")";
lbracket--;
}
}
e += "=";
continue;
}
if (lbracket == 0) {
if (s == ‘(‘) {
e = e + "" + s + "" + (int) (Math.random() * range)
+ "" + symbol[(int) (Math.random() * 4)] + "";
whe[rbracket] = (int) (Math.random()
* (exlength - j - 1) + j + 1);
lbracket++;
rbracket++;
} else {
e = e + "" + (int) (Math.random() * range) + "" + s
+ "";
}
} else if (s != ‘(‘) {
int count2 = lbracket;
int count_match = 0;
for (int l = 0; l < count2; l++) {
if (whe[(rbracket-count2) + l ] == j) {
if (count_match == 0) {
e = e + "" + (int) (Math.random() * range)
+ ")";
count_match++;
lbracket--;
} else {
e += ‘)‘;
lbracket--;
}
}
}
if (count_match == 0) {
e = e + "" + (int) (Math.random() * range) + "" + s
+ "";
} else {
e += "" + s + "";
}
} else {
int count3 = lbracket;
int count = 0;
for (int m = 0; m < count3; m++) {
if (whe[rbracket-count3 + m] == j) {
if (count == 0) {
e = e + "" + (int) (Math.random() * range)
+ ")";
count++;
lbracket--;
} else {
e += ‘)‘;
lbracket--;
}
}
}
if (count == 0) {
e = e + "(" + (int) (Math.random() * range) + ""
+ symbol[(int) (Math.random() * 4)] + "";
whe[rbracket] = (int) (Math.random()
* (exlength - j - 1) + j + 1);
lbracket++;
rbracket++;
} else {
e += "" + symbol[(int) (Math.random() * 4)] + "("
+ (int) (Math.random() * range) + ""
+ symbol[(int) (Math.random() * 4)] + "";
whe[rbracket] = (int) (Math.random()
* (exlength - j - 1) + j + 1);
rbracket++;
lbracket++;
}
}
}
char[] strChar = e.toCharArray();
strChar[strChar.length - 1] = ‘=‘;
for(int g=0 ;g<strChar.length;g++){
if(strChar[g]==‘/‘){
if(strChar[g+1]==‘0‘){
i=i-1;
System.out.print("非法表达式");
}
}
}
System.out.print(eHead);
System.out.println(strChar);
calculate ee = new calculate();
double result = ee.calcualte(e);
out.write(eHead+"答案："+result+"\r\n");
out.flush();
}
out.close();
} catch (Exception e1) {
e1.printStackTrace();
}
}
五.测试运行
文件：
原文地址：https://www.cnblogs.com/378844859-dylan/p/9064183.html
时间： 2024-10-08 23:55:08