Parsing and Scanning Inputs in Java Using Integer.parseInt() and Scanner.nextInt()

Understanding the Difference between Integer.parseInt(scanner.nextLine()) and scanner.nextInt() in Java

In Java, it is important to know the difference between Integer.parseInt(scanner.nextLine()) and scanner.nextInt() when writing a program. Both of these represent ways to input data from the user and store it as an integer. However, there are some key differences that should be understood.

What is Integer.parseInt(scanner.nextLine())?

Integer.parseInt(scanner.nextLine()) is used to parse a String (from the user input) into an integer. This is commonly used when the user is expected to enter an integer value, but the value might contain other characters. For instance, if the user entered "5-3", then the Integer.parseInt(scanner.nextLine()) method would parse it into the integer 5.

What is scanner.nextInt()?

scanner.nextInt() is used to read an integer from the user's input. Unlike Integer.parseInt(scanner.nextLine()), which allows for any kind of data, the user must enter an integer for this to work. If the user enters anything else, then an InputMismatchException will be thrown.

Conclusion

Integer.parseInt(scanner.nextLine()) and scanner.nextInt() are two distinct methods in Java that allow you to accept user input and store it as an integer. While they may seem similar, they have some key differences. It is important to understand these differences so that your code works correctly.