使用switch语句计算字母等级。

/*
nowjava.com - 时  代  Java
*/

import java.util.Scanner; 


public class Main 

{

   public static void main(String[] args)

   {

      int total = 0; // sum of grades                  

      int gradeCounter = 0; // number of grades entered

      int aCount = 0; // count of A grades             

      int bCount = 0; // count of B grades             

      int cCount = 0; // count of C grades             

      int dCount = 0; // count of D grades             

      int fCount = 0; // count of F grades             


      Scanner input = new Scanner(System.in);//来 自 N o w J a v a . c o m - 时  代  Java


      System.out.printf("%s%n%s%n   %s%n   %s%n", 

         "Enter the integer grades in the range 0-100.", 

         "Type the end-of-file indicator to terminate input:", 

         "On UNIX/Linux/Mac OS X type <Ctrl> d then press Enter",

         "On Windows type <Ctrl> z then press Enter");


      // loop until user enters the end-of-file indicator

      while (input.hasNext()) 

      {

         int grade = input.nextInt(); // read grade

         total += grade; // add grade to total

         ++gradeCounter; // increment number of grades

         

         //  increment appropriate letter-grade counter   

         switch (grade / 10)                            

         {                                                

            case 9:  // grade was between 90              

            case 10: // and 100, inclusive                

               ++aCount;         

               break; // exits switch         

                                                          

            case 8: // grade was between 80 and 89        

               ++bCount;            

               break; // exits switch                      

                                                          

            case 7: // grade was between 70 and 79        

               ++cCount;            

               break; // exits switch                      

                                                          

            case 6: // grade was between 60 and 69        

               ++dCount;             

               break; // exits switch                      

                                                          

            default: // grade was less than 60            

               ++fCount;              

               break; // optional; exits switch anyway

         } // end switch                                  

      } // end while 


      // display grade report

      System.out.printf("%nGrade Report:%n");


      // if user entered at least one grade...

      if (gradeCounter != 0) 

      {

         // calculate average of all grades entered

         double average = (double) total / gradeCounter;  


         // output summary of results

         System.out.printf("Total of the %d grades entered is %d%n", 

            gradeCounter, total);

         System.out.printf("Class average is %.2f%n", average);

         System.ou