java定义计算器类Calc：求两个数字加、减、乘、除的结果。创建一个对象，实例化两个数字和符号，输出结果

好的，我知道了。以下是Java定义计算器类Calc并实现求两个数字加、减、乘、除的结果的代码：

public class Calc {
    private double num1;
    private double num2;

    public Calc(double num1, double num2) {
        this.num1 = num1;
        this.num2 = num2;
    }

    public double add() {
        return num1 + num2;
    }

    public double subtract() {
        return num1 - num2;
    }

    public double multiply() {
        return num1 * num2;
    }

    public double divide() {
        if (num2 == 0) {
            throw new ArithmeticException("Cannot divide by zero!");
        }
        return num1 / num2;
    }
}

然后我们可以创建一个对象并实例化两个数字和符号，输出结果：

public static void main(String[] args) {
    double num1 = 10.0;
    double num2 = 5.0;
    String symbol = "+";
    
    Calc calc = new Calc(num1, num2);
    
    switch (symbol) {
        case "+":
            System.out.println(num1 + " + " + num2 + " = " + calc.add());
            break;
        case "-":
            System.out.println(num1 + " - " + num2 + " = " + calc.subtract());
            break;
        case "*":
            System.out.println(num1 + " * " + num2 + " = " + calc.multiply());
            break;
        case "/":
            System.out.println(num1 + " / " + num2 + " = " + calc.divide());
            break;
        default:
            System.out.println("Invalid symbol!");
    }
}

输出结果如下：

10.0 + 5.0 = 15.0

如果符号是其他的，比如 `-` ，输出结果会是：

10.0 - 5.0 = 5.0

以此类推。