I am trying to complete a project that takes a date in the format: Month Day, Year Example: December 1, 1990. After taking in this date, I am trying to output it in the format Month/Day/Year. The method that I am expected to use is substring. I am running into issues with errors when handling misinputs. For example, if there isn't a comma, then an error occurs and the loop is terminated. I am wondering if there is a way to check each value for an error and then continue through the loop if an error is found. Here is my code so far:

 public static void main(String[] args) {
      Scanner scnr = new Scanner(System.in);
                          // Flag to indicate next iteration
      String lineString = "";
      String month;
      int year;
      int day;
      char comma;
            
      lineString = scnr.nextLine();
      while(!lineString.equals(-1)) {
    
       month = lineString.substring(0, lineString.indexOf(" "));
       day = Integer.parseInt(lineString.substring(lineString.indexOf(" ")   1, lineString.indexOf(',') ));   
       comma = lineString.charAt(lineString.indexOf(','));
       year = Integer.parseInt(lineString.substring(lineString.length()-4));
   
       System.out.println(month);
       System.out.println(day);
       System.out.println(comma);
       System.out.println(year);
       
       lineString = scnr.nextLine();
      }

CodePudding user response：

You can wrap your code inside while loop in a try-catch block. It will catch your exception without terminating the program.

CodePudding user response：

One approach is to catch the exceptions. That's the way to deal with the potential exceptions from parseInt; e.g. when the value isn't a valid integer.

Another approach is to make the code more robust so that the exception isn't thrown at all. For example:

• check the results of the indexOf calls to make sure they are not -1 ... which means "not found", and

• don't make assumptions about the number of characters in each field; e.g. lineString.length() - 4

• consider using String.trim() to get rid of additional whitespace.

I think you will need to use both approaches. The key thing is to think of all the mistakes that the user might make and allow for them. It is also a good idea to write your own tests.