2022年java第二次随堂测试（部分问题尚未解决）
四则运算课堂测试二
阶段1：
1、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。
阶段三
3、能处理大数和浮点数计算。
参考：四则运算继承版 - 今天又双叒叕在敲代码 - 博客园 (cnblogs.com)
import java.util.Scanner; import java.util.Random; import java.lang.Math; import java.math.BigDecimal; import java.math.BigInteger; class BigDecimalArithUtil { private static final int DIV_SCALE = 20;//除法精度（除不尽时保留20为小数） /** 小数精确加法 */ public static double add(double d1,double d2) { BigDecimal bd1 = BigDecimal.valueOf(d1); BigDecimal bd2 = BigDecimal.valueOf(d2); return bd1.add(bd2).doubleValue(); } /** 小数精确减法 */ public static double sub(double d1,double d2) { BigDecimal bd1 = BigDecimal.valueOf(d1); BigDecimal bd2 = BigDecimal.valueOf(d2); return bd1.subtract(bd2).doubleValue(); } /** 小数精确乘法 */ public static double mul(double d1,double d2) { BigDecimal bd1 = BigDecimal.valueOf(d1); BigDecimal bd2 = BigDecimal.valueOf(d2); return bd1.multiply(bd2).doubleValue(); } /** 小数精确除法 */ public static double div(double d1,double d2) { BigDecimal bd1 = BigDecimal.valueOf(d1); BigDecimal bd2 = BigDecimal.valueOf(d2); /* * 当除不尽时，以四舍五入的方式（关于除不尽后的值的处理方式有很多种）保留小数点后10位小数 */ return bd1.divide(bd2, DIV_SCALE, BigDecimal.ROUND_HALF_UP).doubleValue(); } } public class three { static int number_test = 0;//题目数目 //普通 static int aa[] = new int[100010]; static int bb[] = new int[100010]; static char cc[] = new char[100010]; static int wrong[] = new int[100010]; static int Ans[] = new int[100010]; //浮点 static double double_aa[] = new double[100010]; static double double_bb[] = new double[100010]; static char double_cc[] = new char[100010]; static double double_wrong[] = new double[100010]; static double double_Ans[] = new double[100010]; //大整数 static BigInteger big_aa[] = new BigInteger[100010]; static BigInteger big_bb[] = new BigInteger[100010]; static char big_cc[] = new char[100010]; static BigInteger big_Ans[] = new BigInteger[100010]; static BigInteger big_wrong[] = new BigInteger[100010]; //查重 public static int check(int[] aa,int [] bb,int i,int j, int n) { for(int k = 0; k <= n; k++) { if((aa[k] == i) && (bb[k] == j)) return 0; } return 1; } //在线答题 public static int online_answer(int a, char c, int b,int answer,int youranswer) { int flag = 0; // if(c == '+') // answer = a + b; // else if (c == '-') // answer = a - b; // else if (c == '*') // answer = a * b; // else if (c == '/') // answer = a / b; // if (answer == youranswer) { flag = 1; return flag; } else { System.out.print("错误！\n"); flag = 0; return flag; } } //在线答题_浮点数 public static int double_online_answer(double a, char c, double b,double answer,double youranswer) { int flag = 0; // if(c == '+') // answer = a + b; // else if (c == '-') // answer = a - b; // else if (c == '*') // answer = a * b; // else if (c == '/') // answer = a / b; // if (BigDecimalArithUtil.sub(answer, youranswer) < 1e-10) { flag = 1; return flag; } else { System.out.print("错误！\n"); flag = 0; return flag; } } //在线答题_大整数 public static int big_online_answer(BigInteger a, char c, BigInteger b,BigInteger answer,BigInteger youranswer) { int flag = 0; // if(c == '+') // answer = a + b; // else if (c == '-') // answer = a - b; // else if (c == '*') // answer = a * b; // else if (c == '/') // answer = a / b; // String a1 = String.valueOf(answer); String a2 = String.valueOf(youranswer) ; // System.out.println(a1); // System.out.println(a2); if (a1.equals(a2)) { flag = 1; return flag; } else { System.out.print("错误！\n"); flag = 0; return flag; } } //错题集 public static void wrong_test_retrain(int aa, char cc, int bb, int wrong) { if (wrong == 1) { System.out.print(aa); System.out.print(cc); System.out.print(bb); System.out.print("="); } } //错题重练 public static int wrong_test_retrain2(int aa, char cc, int bb, int wrong, int answer, int youranswer) { Scanner sc = new Scanner(System.in); int flag = 1; if (wrong == 1) { if (answer == youranswer) { System.out.print("正确！\n"); flag = 1;return flag; } else { System.out.print("又错误！\n"); System.out.print("正确答案："); System.out.print(answer + "\n"); flag = 0;return flag; } } return flag; } //错题集_浮点数 public static void double_wrong_test_retrain(double aa, char cc, double bb, int wrong) { if (wrong == 1) { System.out.print(aa); System.out.print(cc); System.out.print(bb); System.out.print("="); } } //错题重练_浮点数 public static int double_wrong_test_retrain2(double aa, char cc, double bb, int wrong, double answer, double youranswer) { Scanner sc = new Scanner(System.in); int flag = 1; if (wrong == 1) { if (BigDecimalArithUtil.sub(answer, youranswer) < 1e-10) { System.out.print("正确！\n"); flag = 1; return flag; } else { System.out.print("又错误！\n"); System.out.print("正确答案："); System.out.print(answer + "\n"); flag = 0; return flag; } } return flag; } //错题集_大整数 public static void big_wrong_test_retrain(BigInteger aa, char cc, BigInteger bb, int wrong) { if (wrong == 1) { System.out.print(aa); System.out.print(cc); System.out.print(bb); System.out.print("="); } } //错题重练_大整数 public static int big_wrong_test_retrain2(BigInteger aa, char cc, BigInteger bb, int wrong, BigInteger answer, BigInteger youranswer) { Scanner sc = new Scanner(System.in); String a1 = String.valueOf(answer); String a2 = String.valueOf(youranswer) ; int flag = 1; if (wrong == 1) { if (a1.equals(a2)) { System.out.print("正确！\n"); flag = 1;return flag; } else { System.out.print("又错误！\n"); System.out.print("正确答案："); System.out.print(answer + "\n"); flag = 0;return flag; } } return flag; } // public static void main(String[] args) { Scanner sc = new Scanner(System.in); long t = System.currentTimeMillis(); //获得当前时间的毫秒数 Random rand = new Random(t); int a,b,answer = 0; double double_answer = 0.0; BigInteger big_answer = BigInteger.valueOf(0); int youranswer = 0; double double_youranswer = 0.0; BigInteger big_youranswer = BigInteger.valueOf(0); int right_cnt = 0;//正确答题数目 int c_rand; char c = ' '; int number_num = 0;//操作数个数 int number_range = 0;//范围（最大值） int BIG=0; System.out.print("请输入题目数目："); number_test = sc.nextInt(); System.out.print("请输入操作数个数："); number_num = sc.nextInt(); System.out.print("请输入范围（最大值）："); number_range = sc.nextInt(); System.out.print("计算浮点数或大整数（0.普通数据 1.浮点数 2.大整数）(PS:大整数不包含范围是随机的大整数)："); BIG = sc.nextInt(); if (BIG == 0) { for (int i = 0; i < number_test; i++) { a = rand.nextInt(number_range) + 1; b = rand.nextInt(number_range) + 1; aa[i] = a;bb[i] = b; c_rand = rand.nextInt(100)+1; if (c_rand % 4 == 0) { c = '+';cc[i] = c; answer = a + b;Ans[i] = answer; } else if (c_rand % 4 == 1) { c = '-';cc[i] = c; answer = a - b;Ans[i] = answer; } else if (c_rand % 4 == 2) { c = '*';cc[i] = c; answer = a * b;Ans[i] = answer; } else if (c_rand % 4 == 3) { c = '/';cc[i] = c; answer = a / b;Ans[i] = answer; } System.out.print(a); System.out.print(c); System.out.print(b); System.out.print("="); System.out.print("\n"); System.out.print("请输入你的答案："); youranswer = sc.nextInt(); if(online_answer(a,c,b,answer,youranswer) == 0) { wrong[i] = 1;//标记错误 } else { right_cnt++; } } System.out.println("正确率:" + (((double)right_cnt/(double)number_test)*100) + "%"); System.out.print("===错题重练===\n"); for (int i = 0; i < number_test; i++) { int wrong_cnt = 0;//错误次数统计 wrong_test_retrain(aa[i], cc[i], bb[i], wrong[i]); if (wrong[i] == 1) { System.out.print("请输入你的答案："); youranswer = sc.nextInt(); if (wrong_test_retrain2(aa[i], cc[i], bb[i], wrong[i],Ans[i],youranswer) == 0) { wrong_cnt++; } } if (wrong_cnt != 0) { System.out.println("错误次数=" + (wrong_cnt+1)); } System.out.println(""); } } else if (BIG == 1) { for (int i = 0; i < number_test; i++) { double double_a = rand.nextDouble()*number_range; double double_b = rand.nextDouble()*number_range; double_aa[i] = double_a;double_bb[i] = double_b; c_rand = rand.nextInt(100)+1; if (c_rand % 4 == 0) { c = '+';double_cc[i] = c; double_answer = BigDecimalArithUtil.add(double_a, double_b); double_Ans[i] = double_answer; } else if (c_rand % 4 == 1) { c = '-';double_cc[i] = c; double_answer = BigDecimalArithUtil.sub(double_a, double_b); double_Ans[i] = double_answer; } else if (c_rand % 4 == 2) { c = '*';double_cc[i] = c; double_answer = BigDecimalArithUtil.mul(double_a, double_b); double_Ans[i] = double_answer; } else if (c_rand % 4 == 3) { c = '/';double_cc[i] = c; double_answer = BigDecimalArithUtil.div(double_a, double_b); double_Ans[i] = double_answer; } System.out.print(double_a); System.out.print(c); System.out.print(double_b); System.out.print("="); System.out.print("\n"); System.out.print("请输入你的答案："); double_youranswer = sc.nextDouble(); if(double_online_answer(double_a,c,double_b,double_answer,double_youranswer) == 0) { wrong[i] = 1;//标记错误 } else { right_cnt++; } } System.out.println("正确率:" + (((double)right_cnt/(double)number_test)*100) + "%"); System.out.print("===错题重练===\n"); for (int i = 0; i < number_test; i++) { int wrong_cnt = 0;//错误次数统计 double_wrong_test_retrain(double_aa[i], double_cc[i], double_bb[i], wrong[i]); if (wrong[i] == 1) { System.out.print("请输入你的答案："); youranswer = sc.nextInt(); if (double_wrong_test_retrain2(double_aa[i], double_cc[i], double_bb[i], wrong[i],double_Ans[i],double_youranswer) == 0) { wrong_cnt++; } } if (wrong_cnt != 0) { System.out.println("错误次数=" + (wrong_cnt+1)); } System.out.println(""); } } else if (BIG == 2) { for (int i = 0; i < number_test; i++) { int cnt = rand.nextInt(20)+10; int cnt_bits = 0; String number_a = ""; String number_b = ""; for (int j = 0; j < cnt; j++) { cnt_bits = rand.nextInt(9)+1; number_a += cnt_bits; } for (int j = 0; j < cnt; j++) { cnt_bits = rand.nextInt(9)+1; number_b += cnt_bits; } BigInteger big_a = new BigInteger(number_a); BigInteger big_b = new BigInteger(number_b); big_aa[i] = big_a;big_bb[i] = big_b; c_rand = rand.nextInt(100)+1; if (c_rand % 4 == 0) { c = '+';big_cc[i] = c; big_answer = big_a.add(big_b); big_Ans[i] = big_answer; } else if (c_rand % 4 == 1) { c = '-';big_cc[i] = c; big_answer = big_a.subtract(big_b); big_Ans[i] = big_answer; } else if (c_rand % 4 == 2) { c = '*';big_cc[i] = c; big_answer = big_a.multiply(big_b); big_Ans[i] = big_answer; } else if (c_rand % 4 == 3) { c = '/';big_cc[i] = c; big_answer = big_a.divide(big_b); big_Ans[i] = big_answer; } System.out.print(big_a); System.out.print(c); System.out.print(big_b); System.out.print("="); System.out.print("\n"); // System.out.println(big_answer); System.out.print("请输入你的答案："); big_youranswer = sc.nextBigInteger(); // System.out.println(big_answer); // System.out.println(""); if(big_online_answer(big_a,c,big_b,big_answer,big_youranswer) == 0) { wrong[i] = 1;//标记错误 } else { right_cnt++; } } System.out.println("正确率:" + (((double)right_cnt/(double)number_test)*100) + "%"); System.out.print("===错题重练===\n"); for (int i = 0; i < number_test; i++) { int wrong_cnt = 0;//错误次数统计 big_wrong_test_retrain(big_aa[i], big_cc[i], big_bb[i], wrong[i]); if (wrong[i] == 1) { System.out.print("请输入你的答案："); big_youranswer = sc.nextBigInteger(); if (big_wrong_test_retrain2(big_aa[i], big_cc[i], big_bb[i], wrong[i],big_Ans[i],big_youranswer) == 0) { wrong_cnt++; } } if (wrong_cnt != 0) { System.out.println("错误次数=" + (wrong_cnt+1)); } System.out.println(""); } } } }
