Java 用户输入句点时停止的计算器程序

Question

Instructions: Modify your program so that the user is able to chain operations together. Entering an integer, operator, and then another integer should no longer automatically end the program. After displaying to the user the result of the first operation, allow the user to enter another operation and then another integer. The program should then use the result of the first operation as the integer to the left of the operation and the newly entered integer as the integer to the right of the operation. After the result is displayed, the user should be able to type a period (.) to end the program. Once a period is entered, the program should print out the message: “The program has been closed.”

Need help figuring out how to make the program stop when the user enters a period I have tried doing it through do-while Example : 3+5 Result: 8 +3 Result: 11 -5 Result: 6. The program has been closed.

PLEASE HELP

import java.util.Scanner;
class Main {
    static final String VERSION = "1.0";
    public static void main(String[] args) {

    public static void printCalculatorInstructions(){
          System.out.println("Welcome to version "+VERSION+" of the Calculator.");
          System.out.println("In order to use the calculator, do the following:");
          System.out.println("1. Enter the integer that is left of the operator.");
          System.out.println("2. Press enter.");
          System.out.println("3. Enter an operation. Available operations are:\n\t + (addition) \n\t - (subtraction) \n\t * (multiplication) \n\t / (division) \n\t % (remainder) \n\t ^ (exponentiation)");
          System.out.println("4. Press enter.");
          System.out.println("5. Enter the integer to the right of the operator.");
          System.out.println("6. Press enter.");
          System.out.println("7. Look at the result that is printed out!");
      }

        printCalculatorInstructions();

        // Get input for calculator
        Scanner keyboard = new Scanner(System.in);
        int num1 = keyboard.nextInt();
        keyboard.nextLine(); //clear line break character: \n
        String operator = keyboard.nextLine();
        int num2 = keyboard.nextInt();
        int loop = 0;

        do
        {
          //Call the method to perform the calculation based on what operation needs to be used
          if(operator.equals("+")){
            addition(num1, num2);
          }else if(operator.equals("-")){
            subtraction(num1, num2);
          }//you will need to write more else if statements as you implement each of the operators
          else if (operator.equals("*")){
            multiplication(num1, num2);
          }
          else if (operator.equals("/")){
            division(num1, num2);
          }
          else if (operator.equals("%")){
            modulardivision(num1, num2);
          }
          else if (operator.equals("^")){
            exponentiation(num1, num2);
          }

      public static int addition(int a, int b){
          int result = a + b;
          System.out.println("Result: " + result);
          return result;
          result = result +
      }

      public static int subtraction(int a, int b){
          //fill in method here
          int result = a - b;
          System.out.println("Result: " + result);
          return result;
      }

      //write the next method for multiplication here.
      public static int multiplication(int a, int b){
        int result = a * b;
        System.out.println("Result: " + result);
        return result;
      }

      //Then write the methods for division, the % operator, and finally exponentiation.
      public static int division(int a, int b){
        int result = a / b;
        System.out.println("Result: " + result);
        return result;
      }

      public static int modulardivision(int a, int b){
        int result = a % b;
        System.out.println("Result: " + result);
        return result;
      }

      public static double exponentiation(double a, double b){
        double result = Math.pow(a,b);
        System.out.println("Result: " + result);
        return result;
      }


      if (a == .) {
        int loop = 1;
      }

       } while (loop != 1);
}

/* retrun result;
void = nothing is being return   void ! = addition*/ ```

Answer 1

Your code has severe syntax issues.

---

Try this:

import java.util.Scanner;

public class Calculator {
    static final String VERSION = "1.0";

    public static void printCalculatorInstructions(){
        System.out.println("Welcome to version "+VERSION+" of the Calculator.");
        System.out.println("In order to use the calculator, do the following:");
        System.out.println("1. Enter the integer that is left of the operator.");
        System.out.println("2. Press enter.");
        System.out.println("3. Enter an operation. Available operations are:\n\t + (addition) \n\t - (subtraction) \n\t * (multiplication) \n\t / (division) \n\t % (remainder) \n\t ^ (exponentiation)");
        System.out.println("4. Press enter.");
        System.out.println("5. Enter the integer to the right of the operator.");
        System.out.println("6. Press enter.");
        System.out.println("7. Look at the result that is printed out!");
    }

    public static int addition(int a, int b){
        int result = a + b;
        System.out.println("Result: " + result);
        return result;
    }

    public static int subtraction(int a, int b) {
        int result = a - b;
        System.out.println("Result: " + result);
        return result;
    }

    public static int multiplication(int a, int b) {
        int result = a * b;
        System.out.println("Result: " + result);
        return result;
    }

    public static int division(int a, int b) throws ArithmeticException {
        int result = a / b;
        System.out.println("Result: " + result);
        return result;
    }

    public static int modulardivision(int a, int b) {
        int result = a % b;
        System.out.println("Result: " + result);
        return result;
    }

    public static double exponentiation(double a, double b) {
        double result = Math.pow(a, b);
        System.out.println("Result: " + result);
        return result;
    }   

    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);

        boolean toStop = false;

        while (toStop == false) {
            printCalculatorInstructions();

            int num1 = keyboard.nextInt();
            keyboard.nextLine(); //clear line break character: \n
            String operator = keyboard.nextLine();
            int num2 = keyboard.nextInt();

            switch (operator) {
            case "+":
                addition(num1, num2);
                break;
            case "-":
                subtraction(num1, num2);
                break;
            case "*": 
                multiplication(num1, num2);
                break;
            case "/":
                try {
                    division(num1, num2); // in case value of num2 is zero, this won't terminate the program
                } catch (ArithmeticException e) {
                    System.out.println("Value of num2 was zero. Enter a non-zero value for num2.");
                }
                break;
            case "%":
                modulardivision(num1, num2);
                break;
            case "^":
                exponentiation(num1, num2);
                break;
            default:
                toStop = true; // any other operator, character or string entered here will stop the loop
                break;
            }
        }

        keyboard.close();
    }
}

I made a while loop that ran until the boolean condition toStop == false becomes incorrect ie, the value of toStop becomes true . This value will get changed when the user input is anything but the operators you have mentioned. Instead of using if-else statements, I used switch statement to make the process easy to follow.

I hope this helps.