10.23每日总结

完善课上的口算题卡代码，实现重复题目的检测、题目数字范围、加减乘除算式的参数化等扩展功能，提交代码和运行截图。

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import java.util.*;       public class test {       private static String strTest = "";       private static final Random RANDOM = new Random();       private static final Scanner SCANNER = new Scanner(System.in);       private static Integer number_random;           public static void main(String[] args) {               System.out.print("请输入参与数字的最大值：");           number_random = SCANNER.nextInt();               System.out.print("请输入要生成题目数量：");           getExpression(SCANNER.nextInt());       }           /**        * 计算公约数（在下面getExpression方法里面已经排除 0 ）        */       public static int gcd(int a, int b) {           if (a % b == 0) {               return b;           } else {               return gcd(b, a % b);           }       }           /**        * 获取随机运算符        */       public static char getOperator() {           char[] signal = {'+', '-', '*', '/'};           return signal[RANDOM.nextInt(4)];       }               /**        * 生成表达式        */       public static void getExpression(int getNums) {           char operator1, operator2;           int num1, num2, num3;           while (getNums > 0) {               boolean flag = false;               getNums--;               operator1 = getOperator();               operator2 = getOperator();               //保证两个不同的运算符               while (operator1 == operator2) {                   operator1 = getOperator();                   operator2 = getOperator();               }               // + 1 是避免出现 0               num1 = RANDOM.nextInt(number_random) + 1;               num2 = RANDOM.nextInt(number_random) + 1;               num3 = RANDOM.nextInt(number_random) + 1;                   //以下判断只是为了初步判断是否出现小数和负数               if (operator1 == '/') {                   if (gcd(num1, num2) != num2) {                       flag = true;                   }               }               if (operator2 == '/') {                   if (gcd(num2, num3) != num3) {                       flag = true;                   }               }               if (operator1 == '-') {                   if (num1 - num2 <= 0) {                       flag = true;                   }               }               if (operator2 == '-') {                   if (num2 - num3 <= 0) {                       flag = true;                   }               }               if (operator1 == '*') {                   if (num1 * num2 > 99) {                       flag = true;                   }               }               if (operator2 == '*') {                   if (num2 * num3 > 99) {                       flag = true;                   }               }               if (operator1 == '+') {                   if (num1 + num2 > 99) {                       flag = true;                   }               }               if (operator2 == '+') {                   if (num2 + num3 > 99) {                       flag = true;                   }               }               if (flag) {                   getNums++;                   continue;               }               strTest += num1 + "" + operator1 + "" + num2 + "" + operator2 + num3;               String str = calculate(strTest);               strTest = "";               double res = Double.parseDouble(str);               int intRes = (int) res;               if (intRes >= 0 && intRes <= 100) {                   String res2 = "" + num1 + "" + operator1 + "" + num2 + "" + operator2 + "" + num3 + "" + '=' + "" + intRes;                   String replace = res2.replace('/', '÷');                   System.out.println(replace);               } else {                   getNums++;               }           }       }       public static String calculate(String expression) {           List<String> num;           Stack<Double> stack;           num = transformEnd(expression);           stack = new Stack<>();           double sum;           while (!num.isEmpty()) {               String temp = String.valueOf(num.remove(0));               if (isNumber(temp)) {                   double s = Double.parseDouble(temp);                   stack.push(s);               } else {                   double a = stack.pop();                   double b = stack.pop();                   double c = calTwo(b, a, temp);                   stack.push(c);               }           }           sum = stack.pop();           return String.valueOf(sum);       }           /**        * 计算两个值        */       private static double calTwo(double a, double b, String opr) {           double sum = 0.0;           switch (opr) {               case "+":                   sum = a + b;                   break;               case "-":                   sum = a - b;                   break;               case "*":                   sum = a * b;                   break;               case "/":                   sum = a / b;                   break;           }           return sum;       }           /**        * 将中缀表达式转化为后缀表达式（栈是用来进出运算的符号）        */       public static List<String> transformEnd(String expre) {           List<String> sb = new ArrayList<>();           Stack<String> stack = new Stack<>();           expre = expre.replaceAll("(\\D)", "o$1o");           String[] esp = expre.trim().split("o");           for (String value : esp) {               String s = value.trim();               if (isNumber(s)) {                   // 如果是数字则输出                   sb.add(s);               } else if (!s.isEmpty()) {                   if (!stack.isEmpty() && !isMaxExp(s.charAt(0), stack.peek().charAt(0))) {                       while (!stack.isEmpty() && !isMaxExp(s.charAt(0), stack.peek().charAt(0))) {                           sb.add(stack.pop());                       }                   }                   stack.push(s);               }           }           while (!stack.isEmpty()) {               sb.add(stack.pop());           }           return sb;       }           /**        * 判断是否是数字        */       private static boolean isNumber(String str) {           try {               Double.parseDouble(str);           } catch (RuntimeException e) {               return false;           }           return true;       }           /**        * 判断两个操作符优先级        */       private static boolean isMaxExp(char exp1, char exp2) {           return transExp(exp1) > transExp(exp2);       }           /**        * 优先级        */       private static int transExp(char exp) {           int re = 0;           switch (exp) {               case '*':               case '/':                   re = 2;                   break;               case '+':               case '-':                   re = 1;                   break;           }           return re;       }       }