做一个简单的计算器，但我需要添加一些东西

我为Java分配做了一个非常简单的计算器，但是当用户输入一个非数字时，我陷入了需要添加文本的部分。我需要在其中添加什么？需要在哪里添加它才能起作用？我尝试了多种在Internet上搜索的方法，但是似乎都没有。

从技术上讲，这种方式有效，但是由于某种原因，它前后总是带有红色文本。

public class MySwitchExample {
    public static void main(String[] args) {
        char operator;
        double num1;
        double num2;
        double result;
        
    
        Scanner s= new Scanner(System.in);
        System.out.print("Enter operator (either +, -, * or /): ");
        operator= s.next().charAt(0);
        
        System.out.print("Enter number 1 and number 2: ");
          try {
              num1= Double.parseDouble(s.next());
              num2= Double.parseDouble(s.next());
           } catch (NumberFormatException e) {
              // Double.parseDouble has changed specs several times, so fall through
              // gracefully
              e.printStackTrace();
              System.out.print("You entered text as a number: ");
              return;
           }
      
        
                 switch (operator) {
        
                    // performs addition between numbers
                    case '+':
                        result = num1 + num2;
                        System.out.print(num1 + "+" + num2 + " = " + result);
                        break;
            
                        // performs subtraction between numbers
                    case '-':
                        result = num1 - num2;
                        System.out.print(num1 + "-" + num2 + " = " + result);
                        break;
            
                        // performs multiplication between numbers
                    case '*':
                        result = num1 * num2;
                        System.out.print(num1 + "*" + num2 + " = " + result);
                        break;
                        // performs division between numbers
                    case '/':
                        result = num1 / num2;
                        System.out.print(num1 + "/" + num2 + " = " + result);
                        break;
                        
                        
            
                    default:
                        System.out.println("Invalid operator!");
                        break;
                    
        }
      }
    }