Is there a way to return to a previous line of code (without a while loop)-CodePudding

I'm trying to create something that includes a part which receives an input and checks if a respective file exists(and if the input was a number) like so:

short x = 0;
Scanner scan = new Scanner(System.in);
try {
                    x = scan.nextShort(); 
                    Path path = Paths.get(x   ".ics");
                    if(!Files.exists(path)) {
                        System.out.println("Sorry, file does not exist");
                        System.exit(0);
                    }
                }       catch(InputMismatchException e) { 
                    System.out.println("Sorry, please enter a number");
                    System.exit(0);
                    }   
 File f = new File(x   ".ics");  
                try (Scanner classScan = new Scanner(f)) { 
                    byte i = 1; 
                    for(; i <=6; i   ) { 
                        if(classScan.findWithinHorizon(i, 0) != null) {
                            break; 
                            
                        }
                    }
                    System.out.println(i); 
                }
            }

At the two System.exit lines I want to create something that returns to scan.nextShort() - I thought about a while loop but I can't think of a plausible way to do that here (especially with an exception catch).

I also want to run code under the try-catch if neither the if statement or catch happens.

Title is partly misleading if there's actually a way to do this with a while loop I would appreciate it.

CodePudding user response：

Maybe while (scan.hasMoreElements()) outside the try block.

CodePudding user response：

A do { .. } while; can be applied here as in below. Just add a boolean flag initial false and set to true when correct input is found.

And note you need a scan.next() in the InputMismatchException processing otherwise it will continue to scan the same invalid input:

// assume test created a file named '3.ics'

short x = 0;
Scanner scan = new Scanner(System.in);
boolean valid = false;
do {
    try {
        x = scan.nextShort(); 
        Path path = Paths.get(x   ".ics");
        if(!Files.exists(path)) {
            System.out.println("Sorry, file does not exist");
        } else {
            valid = true;
        }
    } catch(InputMismatchException e) { 
        System.out.println("Sorry, please enter a number");
        scan.next();
    }   
} while (!valid);

System.out.println(x   ".ics"); 
// ... and on we go ...

And output

abc
Sorry, please enter a number
2
Sorry, file does not exist
3
3.ics