javatypesintdoublemetadatatype

How to determine numeric Data Type in Java?

I want to know whether the user inputs a char or an int, and hence take a different course of action depending upon the data type.

Solution

  • You can read line as String and then check string with regex. For example if you are reading from stdin

    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

String inputString = bufferedReader.readLine();

String doubleRegex = "[-+]?[0-9]*\\.?[0-9]+([eE][-+]?[0-9]+)?";
String integerRegex = "[-+]?[0-9]+";

if (inputString.matches(integerRegex)) {
    System.out.println("integer");
} else
if (inputString.matches(doubleRegex)) {
    System.out.println("double");
} else {
    // Error inputted string can't be parsed
}