#include <iostream.h>
#include <fstream.h>
#include "apvector.h"
#include "apstring.h"

const int NUM_GRADES = 4;                  // # different grades

class GradeInfo
{
  public:
 
      GradeInfo();                        // constructor
      void Read(istream & input);         // read info from input
      void PrintBarGraph();               // print bar graph of grades
    
  private:

    int CharToIndex(char ch);  // convert char to index

    apvector<int> myGrades;    // # occurrences of each grade
    int           myCount;     // total # of grades   
};


GradeInfo::GradeInfo()
    : myGrades(NUM_GRADES,0),
      myCount(0)
{
    // myGrades initialized to NUM_GRADES cells, all equal to 0
}

int GradeInfo::CharToIndex(char ch)
// precondition: 'A' <= ch <= 'D'
// postcondition: returns int index corresponding to ch    
{
    return ch - 'A';
}

void GradeInfo::Read(istream & input)
// precondition: input is open for reading
// postcondition: myGrades contains the frequency count of
//                each grade in input,
//                myCount contains the total number of grades
//                in input
{
    int k,index;
    char ch;

    // initialize all counters to 0
    
    for(k=0; k < NUM_GRADES; k++)   
    {
        myGrades[k] = 0;
    }

    // read file

    while (input >> ch)
    {
        index = CharToIndex(ch);  // map char to an index
        myGrades[index]++;        // bump # occurrences
        myCount++;                // bump total count
    }   
}

void GradeInfo::PrintBarGraph()
{
    int k,index;
    char ch;

    for(ch = 'A'; ch <= 'D'; ch++)
    {
        index = CharToIndex(ch);

        for(k=0; k < myGrades[index]; k++)
        {
            cout << ch;
        }
        cout << endl;
    }

    cout << "Total Grades = " << myCount << endl;
}