在这个由扫描器类和Java编写的简单计算器程序中，使用字符串中止“中止” while循环

Question

Please help me to abort the while loop with sc.equals("abort") input/n at any time in the process.

  public class Calculator {
        public static void main(String[] args) {
            double wert1, wert2, ergebnis;
            Scanner sc = new Scanner(System.in);
            boolean start = true;
            while(start) {
                try {
                    System.out.println("Pleaser Enter First Number");
                    wert1 = sc.nextDouble();

                    System.out.println("please Enter a Operator +,-,/,*");
                    String operator = sc.next();

                    System.out.println("please Enter second Value");
                    wert2 = sc.nextDouble();

                    if (operator.equals("+")) {
                        ergebnis = wert1 + wert2;
                        System.out.println("Das Ergebnis ist " + ergebnis);
                    }
                    if (operator.equals("-")) {
                        ergebnis = wert1 - wert2;
                        System.out.println("Das Ergebnis ist " + ergebnis);
                    }
                    if (operator.equals("*")) {
                        ergebnis = wert1 * wert2;
                        System.out.println("Das Ergebnis ist " + ergebnis);
                    }
                    if (operator.equals("/")) {
                        ergebnis = wert1 / wert2;
                        System.out.println("Das Ergebnis ist " + ergebnis);
                    }
                    if (sc.equals("abort")) {//why doesnt this work?
                        start = false;
                        break;
                    }
                } catch (InputMismatchException e) {

                    if (sc.equals("abort")) {//why doesnt this work?
                        start = false;
                        break;
                    }
                    else{sc.nextLine();}
                }
            }
        }
    }

Abort with a string "abort" a while-loop in this simple calculator program made with scanner class and Java.

Answer 1

sc is the Scanner object, it does not represent directly what you type. You can retrieve what you type with sc.next() . You already defined String operator = sc.next() , so just use if (operator.equals("abort")) instead of if (sc.equals("abort")) .