java - 该方法未定义类型 - 多态性

Question

我不完全确定如何解决这个问题，但是我在子类“Complex”中的乘法和除法方法上遇到了未定义的类型错误。我的“复杂”类应该扩展我的“简单”类。错误信息如下：

• 对于 Simple 类型，方法 multiply(int, int) 未定义。
• 未定义 Simple 类型的方法 multiply(int, int, int)

• 对于 Simple 类型，没有定义方法 divide(int, int)。

  import java.util.Scanner;
  class Simple {
      public int sum(int a, int b) {
          return (a + b);
      }
  
  public int sum(int a, int b, int c) {
      return (a + b + c);
  }
  
  public int remainder(int a, int b) {
      return (a - b);
  }
  

  }

  class Complex extends Simple {
  public int multiply(int a, int b) {
      return (a * b);
  }
  
  public int multiply(int a, int b, int c) {
      return (a * b * c);
  }
  
  public int divide(int a, int b) {
      return (a / b);
  }
  

  }

  class CalculatorTest {
  public static void main(String[] args) {
      // Scanner, object instance
      Scanner input = new Scanner(System.in);
  
      // Capture arguments, math operation
      System.out.print("Input math operation: [A]dd, [S]ubtract, [M]ultiply, [D]ivide: ");
      char mathOp = input.next().toUpperCase().charAt(0);
      System.out.print("Input 3 arguments each followed by a space: ");
      int int1 = input.nextInt();
      int int2 = input.nextInt();
      int int3 = input.nextInt();
  
      // Math operations selection structure
      if (mathOp == 'A' || mathOp == 'S') {
          Simple calculator = new Simple();
          if (mathOp == 'A') {
              System.out.print(int1 + " + " + int2 + " = " + calculator.sum(int1, int2) + "\n");
              System.out.print(int1 + " + " + int2 + " + " + int3 + " = " + calculator.sum(int1, int2, int3) + "\n");
          } else if (mathOp == 'S') {
              System.out.print(int1 + " - " + int2 + " = " + calculator.remainder(int1, int2) + "\n");
          }
      } else {
          Simple calculator1 = new Complex();
          if (mathOp == 'M') {
              System.out.print(int1 + " x " + int2 + " = " + calculator1.multiply(int1, int2) + "\n");
              System.out.print(int1 + " x " + int2 + " x " + int3 + " = " + calculator1.multiply(int1, int2, int3) + "\n");
          } else if (mathOp == 'D') {
              System.out.print(int1 + " / " + int2 + " = " + calculator1.divide(int1, int2) + "\n");
          }
      }
  }
  

  }

标签： javapolymorphism