一、定义方法验证题目是否重复；并将出题参数用子方法定义。 2、定义随机数生成器子方法，根据出题参数（出题个数、操作数的个数、确定操作数的取值范围）生成全部的随机操作数。
阶段2： 1、定义方法实现在线答题；全部完成后，显示答题结果，输出正确率和错题。 2、定义方法实现错题集、错题重练并记录错题的次数功能。
1 package Test;
2
3 import java.util.Random;
4 import java.util.Scanner;
5
6 public class Math_4 {
7 static int n ;
8 static int fw ;
9
10 static char[] f = new char[100010];
11 static int [] s1 = new int [100010];
12 static int [] s2 = new int [100010];
13 static int t = 0;
14 static int [] answer = new int [100010];
15 static int [] ben = new int [100010];
16 static int x = 0;
17 static int y = 0;
18 static int s = 1;
19 static Scanner sc = new Scanner(System.in);
20 public static void main(String[] args) {
21
22 Top();
23 init();
24 for(int i = 0 ; i< n ;i++)
25 {
26 x++;
27 Show(x);
28 }
29 Shownum();
30 replay();
31
32 }
33 public static void Top()
34 {
35 System.out.println("请输入一共输入多少个");
36 n = sc.nextInt();
37 System.out.println("请输入范围");
38 fw=sc.nextInt();
39 }
40 public static int random(int w) //随机数生成器
41 {
42 Random rm=new Random(); //随机数
43
44 return rm.nextInt(w) + 1;
45 }
46 public static void init()
47 {
48 for(int i = 0 ; i < n ; i ++)
49 {
50 t++;
51 //符号
52 int number_3;
53 number_3 = random(4);
54 //数字
55 int number_1 = random(fw);
56 int number_2 = random(fw);
57 s1[t] = number_1 ;
58 s2[t] = number_2 ;
59
60 if(number_3==1)
61 {
62 f[t] = '+';
63 answer[s++] = number_1 + number_2;
64 }
65 else if(number_3==2)
66 {
67 f[t] = '-';
68 answer[s++] = number_1 - number_2;
69 }
70 else if (number_3==3)
71 {
72 f[t] = '*';
73 answer[s++] = number_1 * number_2;
74 }
75 else if(number_3==4)
76 {
77 f[t] = '/';
78 answer[s++] = number_1 / number_2;
79 }
80 }
81 }
82 public static void Show(int x)
83 {
84 System.out.print(s1[x]);
85
86 if(f[x] == '+')
87 {
88
89 System.out.print("+");
90 }
91 else if(f[x] == '-')
92 {
93
94 System.out.print( "-" );
95 }
96 else if (f[x] == '*')
97 {
98
99 System.out.print( "*" );
100 }
101 else if(f[x] == '/')
102 {
103
104 System.out.print( "/" );
105 }
106
107 System.out.print(s2[x]);
108 System.out.println( "=\t\t" );
109 int d = sc.nextInt();
110 if(d != answer[x])
111 {
112 System.out.println( "答案错误" );
113 ben[y++] = x;
114 }
115 }
116 public static void replay()
117 {
118 System.out.println("错题本重练系统");
119 for(int i = 0 ; i < y ;i++)
120 {
121 Show(ben[i]);
122 }
123 }
124 public static void Shownum()
125 {
126 System.out.println("错题个数: " + y);
127 int b = (n-y)*10/n*10;
128 int d = b + (n-y)*10%n*10/n;
129 System.out.println("正确率: " + d + "%" );
130
131 }
132 }
阶段三 3、 改造程序，可以实现浮点数精确计算。 可以实现无限大的整数的计算。
1 package Test;
2
3 import java.math.BigInteger;
4 import java.util.Random;
5 import java.util.Scanner;
6
7 public class Math_5 {
8 static int n ;
9 static int flag ;
10 static int fw ;
11
12 static char[] f = new char[100010];
13 static double [] s1 = new double [100010];
14 static double [] s2 = new double [100010];
15 static BigInteger [] s3 = new BigInteger [100010];
16 static BigInteger [] s4 = new BigInteger [100010];
17
18 static int t = 0;
19 static double [] answer = new double [100010];
20 static int [] ben = new int [100010];
21 static BigInteger [] answer1 = new BigInteger [100010];
22
23 static int x = 0;
24 static int y = 0;
25 static int s = 1;
26 static Scanner sc = new Scanner(System.in);
27 public static void main(String[] args) {
28
29 Top();
30 if(flag == 1)
31 {
32 init1();
33 for(int i = 0 ; i< n ;i++)
34 {
35 x++;
36 Show(x);
37 }
38 Shownum();
39 replay();
40 }
41 else if (flag == 2)
42 {
43 init2();
44 for(int i = 0 ; i< n ;i++)
45 {
46 x++;
47 Show2(x);
48 }
49 Shownum();
50 replay2();
51 }
52
53 }
54 public static void Top()
55 {
56 System.out.println("请输入一共输入题目个数");
57 n = sc.nextInt();
58
59 System.out.println("请输入浮点数: 1 ; 大整数: 2");
60 flag=sc.nextInt();
61 System.out.println("请输入数字范围");
62 if(flag == 2)
63 {
64 BigInteger big;
65 big=sc.nextBigInteger();
66 }
67 else
68 fw=sc.nextInt();
69 }
70
71 public static double random1(int w) //随机浮点数生成器
72 {
73 Random rm=new Random(); //随机数
74
75 return rm.nextDouble(w) + 1;
76 }
77 public static int random(int w) //随机数生成器
78 {
79 Random rm=new Random(); //随机数
80
81 return rm.nextInt(w) + 1;
82 }
83 public static void init1() //浮点数生成
84 {
85 for(int i = 0 ; i < n ; i ++)
86 {
87 t++;
88 //符号
89 int number_3;
90 number_3 = random(4);
91 //数字
92 double number_1 = random1(fw);
93 double number_2 = random1(fw);
94 s1[t] = number_1 ;
95 s2[t] = number_2 ;
96
97 if(number_3==1)
98 {
99 f[t] = '+';
100 answer[s++] = Arith.add(number_1, number_2);
101 }
102 else if(number_3==2)
103 {
104 f[t] = '-';
105 answer[s++] = Arith.sub(number_1 , number_2);
106 }
107 else if (number_3==3)
108 {
109 f[t] = '*';
110 answer[s++] =Arith.mul(number_1 , number_2);
111 }
112 else if(number_3==4)
113 {
114 f[t] = '/';
115 answer[s++] = Arith.div(number_1 , number_2);
116 }
117 }
118 }
119 public static void init2() //大整数生成
120 {
121 for(int i = 0 ; i < n ; i ++)
122 {
123 t++;
124 //符号
125 int number_3;
126 number_3 = random(4);
127 //数字
128
129 System.out.println("输入题目");
130 BigInteger n1 = sc.nextBigInteger();
131 BigInteger n2 = sc.nextBigInteger();
132 s3[t] = n1 ;
133 s4[t] = n2 ;
134
135 if(number_3==1)
136 {
137 f[t] = '+';
138 answer1[s++] = n1.add(n2);
139 }
140 else if(number_3==2)
141 {
142 f[t] = '-';
143 answer1[s++] = n1.subtract(n2);
144 }
145 else if (number_3==3)
146 {
147 f[t] = '*';
148 answer1[s++] = n1.multiply(n2);
149 }
150 else if(number_3==4)
151 {
152 f[t] = '/';
153 answer1[s++] = n1.divide(n2);
154 }
155 }
156 }
157 public static void Show(int x) //显示浮点数
158 {
159 System.out.print(s1[x]);
160
161 if(f[x] == '+')
162 {
163
164 System.out.print("+");
165 }
166 else if(f[x] == '-')
167 {
168
169 System.out.print( "-" );
170 }
171 else if (f[x] == '*')
172 {
173
174 System.out.print( "*" );
175 }
176 else if(f[x] == '/')
177 {
178
179 System.out.print( "/" );
180 }
181
182 System.out.print(s2[x]);
183 System.out.println( "=\t\t" );
184 System.out.println( "输入答案: 保留小数点后14位" );
185 double d = sc.nextDouble();
186 if(d != answer[x])
187 {
188 System.out.println( "答案错误" );
189 System.out.println( "正确答案: " + answer[x]);
190 ben[y++] = x;
191 }
192 }
193 public static void Show2(int x) //显示大整数
194 {
195 System.out.print(s3[x].toString());
196
197 if(f[x] == '+')
198 {
199
200 System.out.print("+");
201 }
202 else if(f[x] == '-')
203 {
204
205 System.out.print( "-" );
206 }
207 else if (f[x] == '*')
208 {
209
210 System.out.print( "*" );
211 }
212 else if(f[x] == '/')
213 {
214
215 System.out.print( "/" );
216 }
217
218 System.out.print(s4[x].toString());
219 System.out.println( "=\t\t" );
220 BigInteger d = sc.nextBigInteger();
221 if(d != answer1[x])
222 {
223 System.out.println( "答案错误" );
224 System.out.println( "正确答案: " + answer1[x].toString());
225 ben[y++] = x;
226 }
227 }
228 public static void replay() //浮点数重练
229 {
230 System.out.println("错题本重练系统");
231 for(int i = 0 ; i < y ;i++)
232 {
233 Show(ben[i]);
234 }
235 }
236 public static void replay2() //大整数重练
237 {
238 System.out.println("错题本重练系统");
239 for(int i = 0 ; i < y ;i++)
240 {
241 Show2(ben[i]);
242 }
243 }
244 public static void Shownum() //统计正确率
245 {
246 System.out.println("错题个数: " + y);
247 int b = (n-y)*10/n*10;
248 int d = b + (n-y)*10%n*10/n;
249 System.out.println("正确率: " + d + "%" );
250
251 }
252 }
标签：int,四则运算,number,System,++,static,测试,课堂,out From： https://www.cnblogs.com/fan-wang/p/16704371.html