Question

我遇到的一个问题是我无法使用Camel案例。我必须使用Pascal。我在纠正下面的代码时发现，当我将int更改为像我们的教师想要的那样时，我得到一个无法打开double类型的值。

我正在尝试寻找其他东西而不是可以让我获得相同功能的开关。任何帮助表示赞赏。谢谢！

import java.util.Random;
import java.util.Scanner;

public class CalculatorWithMethods {

// scanner object creation
static Scanner input = new Scanner(System.in);
boolean mainloop = true;

public static void main(String[] args) {

    //Declaring variables
    double res;

    //calling the method
    double choice = getMenuOption();


    switch (choice) {
    case 1:
    {
        //calling the method to get the operands
        double operand1 = getOperand("What is the first number?");
        double operand2 = getOperand("What is the second number?");
        res = add(operand1, operand2);
        System.out.println(operand1 + " + " + operand2 + " = " + res);
        break;
    }
    case 2:
    {
        //calling the method to get the operands
        double operand1 = getOperand("What is the first number?");
        double operand2 = getOperand("What is the second number?");
        res = subtract(operand1, operand2);
        System.out.println(operand1 + " - " + operand2 + " = " + res);
        break;
    }
    case 3:
    {
        //calling the method to get the operands
        double operand1 = getOperand("What is the first number?");
        double operand2 = getOperand("What is the second number?");
        res = multiply(operand1, operand2);
        System.out.println(operand1 + " * " + operand2 + " = " + res);
        break;
    }
    case 4:
    {
        //calling the method to get the operands
        double operand1 = getOperand("What is the first number?");
        double operand2 = getOperand("What is the second number?");
        if (operand2 == 0) {
            System.out.println("The Second Number is Double.NAN.");
        } else {
            //calling the method to get the operands
            operand1 = getOperand("What is the first number?");
            operand2 = getOperand("What is the second number?");
            res = divide(operand1, operand2);
            System.out.println(operand1 + " / " + operand2 + " = " + res);
        }
        break;
    }
    case 5:
    {
        double operand1 = getOperand("What is the lower limit ?");
        double operand2 = getOperand("What is the upper limit ?");
        res = random(operand1, operand2);
        System.out.println("The Random Number is :" + res);
        break;
    }
    }
}

//This method will perform the add operation
public static double add(double operand1, double operand2) {

    return operand1 + operand2;
}

//This method will perform the subtract operation
public static double subtract(double operand1, double operand2) {

    return operand1 - operand2;
}

//This method will perform the multiply operation
public static double multiply(double operand1, double operand2) {
    return operand1 * operand2;
}
//This method will perform the division operation
    public static double divide(double operand1, double operand2) {

        return operand1 / operand2;
    }
//This method returns the random number
public static double random(double x, double y) {
    Random generator = new Random();

    return generator.nextInt((int)(y - x) + 1) + x;
}

//This method will get the operands entered by the user
public static double getOperand(String str) {

    System.out.print(str);
    double num = input.nextDouble();
    return num;
}

//This method will display the menu
public static int getMenuOption() {

    int choice;

    // user interaction until quit performed.
    while (true) {

        // displaying menu
        System.out.println("\nMenu\n1. Add\n2. Subtract\n3. Multiply\n4. Divide\n5. Generate Random Number\n6. Quit");

        // ask user choice
        System.out.println("What would you like to do?");

        choice = input.nextInt();

        if (choice < 1 || choice > 5) {
            System.out.println("** Invalid Choice **");
            continue;
        } else {
            return choice;
        }
    }
}

}

Answer 1

之后：

a.foo = 42

这样做：

a.foo=(42)

然后切换intCastedChoice。

因为我不能使用开关，所以使用双倍的东西？

1 个答案: