Как посчитать max/ min используя только relational operators?

* Purpose: Calculate maximum, minimum and average of 5 numbers
 */
 
/******************************************************************************************
impotr statement that makes the class JOptionPane class available to the programmer-defined
*******************************************************************************************/
 
import javax.swing.JOptionPane; //an import statement for GUI/
 
 
 
public class MinMaxAvg //definition of class that calculates maximum, minimum and average of 5 numbers
{
 
   // main method
   public static void main( String[] args )
   {
 
       /**********************************************************************
       declare and initialize variables
       **********************************************************************/
      String openingMessage = "This program finds the minimum, \n maximum, and average of five numbers.\n",
             enterMessage1,
             enterMessage2,
             enterMessage3,
             enterMessage4,
             enterMessage5,
 
             enterChoice,
 
 
             outputMessage;
 
 
         int      choice;
         double   num1,
                  num2,
                  num3,
                  num4,
                  num5,
                  calculation;
 
 
 
      /**********************************************************************
       input
       **********************************************************************/
        JOptionPane.showMessageDialog(null, openingMessage); // show introduction message for program
 
        // show input dialog boxes to input  5 numbers:
        enterMessage1 = JOptionPane.showInputDialog("Enter 1st number");
 
        enterMessage2 = JOptionPane.showInputDialog("Enter 2nd number");
 
        enterMessage3 = JOptionPane.showInputDialog("Enter 3rd number");
 
        enterMessage4 = JOptionPane.showInputDialog("Enter 4th number");
 
        enterMessage5 = JOptionPane.showInputDialog("Enter 5th number");
 
 
        //show select input dialog box to choose one of methods to calculate  maximum or minimum or average:
        enterChoice = JOptionPane.showInputDialog("Select\n\n 1 to find the minimum, \n 2 to find the maximum,\n 3 to find the average\n\n");
 
 
      /**********************************************************************
       processing
       **********************************************************************/
 
       //Converting input strings to numbers:
       num1 = Double.parseDouble(enterMessage1);  // convert string enterMessage1 to double
 
       num2 = Double.parseDouble(enterMessage2);  // convert string enterMessage2 to double
 
       num3 = Double.parseDouble(enterMessage3);  // convert string enterMessage3 to double
 
       num4 = Double.parseDouble(enterMessage4);  // convert string enterMessage4 to double
 
       num5 = Double.parseDouble(enterMessage5);  // convert string enterMessage5 to double
 
       choice =  Integer.parseInt(enterChoice);  // convert string enterChoice to integer number to moke a selection
 
 
 
 
       //calculate maximum, minimum and average of 5 numbers:
 
       if (choice == 1)
 
                calculation = max // здесь загвоздка
 
       else if (choice == 2)
 
                calculation = min  // здесь загвоздка
            else
            calculation = (num1 + num2 + num3 + num4 + num5)/5;
 
 
 
       /**********************************************************************
            output
       **********************************************************************/
            outputMessage = "Original numbers are: "    + num1 + ", " + num2 + ", " + num3 + ", " + num4 + ", " + num5 + "\n\n" + calculation;
                // switch (choice)
                 //  {
                    //   case 1:
 
                        //   "The maximum value is   "  + max break;
 
                     //   case 2:
 
                           // "The minimum value is   "  + min break;
 
                    //    case 3:
 
                            // "The average value is   "  + ave   break;
 
 
 
            JOptionPane.showMessageDialog( null, outputMessage ); //print appropriate output of calculation  on the screen
 
      System.exit(0);
 
    } // end main
 
} // end class