Saving the Month

It is possible to save run-time objects to disk. This is an advanced topic.

Here is an expanded MonthTester that gives the user the option to save the data to a file as text. If you have not yet looked at file I/O, skip this page.

An improvement to the program would ask the user for the filename. Another improvement would be to have the option to read in data from a file. Sounds like a great idea for a programming exercise.


public class MonthTester
{
  public static void main( String[] args)  throws IOException
  {
    Scanner scan = new Scanner( System.in );
    Month jan = new Month( 1, 2017 ) ;
    String line = "Y";
    
    // Fill Month with temperatures
    while ( line.toUpperCase().charAt(0) == 'Y' )
    {
      System.out.print("day?  ");
      int day = scan.nextInt();
      
      System.out.print("temp ? ");
      int low = scan.nextInt();
      if ( !jan.setTemp(day, low ) )
        System.out.println("error in input");
 
      System.out.print("Continue (Y/N)? ");
      line = scan.next();
    }

    System.out.println( jan );  
    int validDays = jan.countValidDays();
     
    if ( validDays > 0 )
    {
      System.out.println( "Average Temperature: " +  jan.avgTemp() );
    }
     
    // Save Data to a File
    System.out.print("Save to file (Y/N)? ");
    line = scan.next();
    if ( line.toUpperCase().charAt(0) == 'Y' )
    {
      PrintWriter output = new PrintWriter( "monthData.txt" );
      output.print( jan.toString() ) ;
      output.close();
    }
  }
  
}

The main() method must include throws IOException because creating a PrintWriter might fail.

Answer:

Saving the Month

QUESTION 12: