JAVA HOW TO PROGRAM, NINTH EDITION, DEITEL: CHAPTER SIX SOLUTIONS

Questions: Temperature Conversions

Implement the following integer methods:
a) Method celsius returns the Celsius equivalent of a Fahrenheit temperature, using the calculation

celsius = 5.0 / 9.0 * ( fahrenheit - 32 );

b) Method fahrenheit returns the Fahrenheit equivalent of a Celsius temperature, using the calculation

fahrenheit = 9.0 / 5.0 * celsius + 32;

c) Use the methods from parts (a) and (b) to write an application that enables the user either to enter a Fahrenheit temperature and display the Celsius equivalent or to enter a Celsius temperature and display the Fahrenheit equivalent.

Solutions: Temperature Conversions

// Program converts Fahrenheit to Celsius. and vice versa.
import java.util.Scanner;

public class TemperatureConversion
{
  public static void main (String [] args)
  {
  Scanner input = new Scanner( System.in );
     
      int choice; // the user's choice in the menu
     
      do
      {
         // print the menu
         System.out.println( "1 Fahrenheit to Celsius" );
         System.out.println( "2 Celsius to Fahrenheit" );
         System.out.println( "3 Exit" );
         System.out.print( "Choice: " );
         choice = input.nextInt();
        
         if ( choice != 3 )
         {
            System.out.print( "Enter temperature: " );
            int oldTemperature = input.nextInt();

            // convert the temperature appropriately
           
            switch ( choice )
            {
               case 1:
                  System.out.printf( "%d Fahrenheit is %d Celsius\n",
                     oldTemperature, celsius( oldTemperature ) );
                  break;

               case 2:
                  System.out.printf( "%d Celsius is %d Fahrenheit\n",
                    oldTemperature, fahrenheit( oldTemperature ) );
                  break;
                 
              default:
                    System.out.println("Wrong Choice, try again!");
            } // end switch
         } // end if
    
      }// end do
     
      while ( choice != 3 );
  
      } // end method main

       
   // return Celsius equivalent of Fahrenheit temperature
   public static int celsius( int fahrenheitTemperature )
   {
      return ( (int) ( 5.0 / 9.0 * ( fahrenheitTemperature - 32 ) ) );
   } // end method celsius

   // return Fahrenheit equivalent of Celsius temperature
   public static int fahrenheit( int celsiusTemperature )
   {
      return ( (int) ( 9.0 / 5.0 * celsiusTemperature + 32 ) );
   } // end method fahrenheit
} // end class TemperatureConversion