Numeric Input

The command line data are always Strings. But this does not prevent you from entering numbers. Use Integer.parseInt(String) or Double.parseDouble(String) to convert the character data to numeric data. The Integer class is a wrapper class that contains several useful methods, such as this one for converting between characters and int. The Double class is also a wrapper class. Here is an example:

class InputDemo
{
  public static void main ( String[] args )
  {
    int sum = 0;
    for (int j=0; j  < args.length; j++ )

      sum += Integer.parseInt(  );

    System.out.println( "Sum: " + sum );
  }
}

Say that the user started this program with the command line:

C:\>java InputDemo 23 87 13 67 -42