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//***************************************************************
//  Programmer: Bob Comer
//
//  Purpose:
//  A class takes 4 tests during a semester. This program
//  calculates and prints each student's test average, and
//  the class average for each test. The test grades are in a
//  data file - each line has the 4 test grades for 1 student
//  (maximum of 25 students).
//
//***************************************************************

#include 
#include 
#include 

const int MAX_STUDENTS = 25;    // The maximum class size
const int NUM_TESTS = 4;        // Number of tests in a semester

// Prototypes
void GetGrades( ifstream&, int[][4], int&);
void CalcClassAvg( const int grade[][4], 
			 int numStudents,
		       float classAvg[]);
void CalcStudentAvg( const int grade[],
			float& studentAvg);
void PrintTests( const int grade[][4],
		     float studentAvg[], 
		       int numStudents, 
		     float classAvg[]);

int main()
{
   ifstream gradeFile;                  // Input file of grades

   int grade[MAX_STUDENTS][NUM_TESTS]; // Semester test grades
   float studentAvg[MAX_STUDENTS];     // Students test average
   float classAvg[NUM_TESTS];          // Class avg for each test
   int numStudents;                    // Number of students
   int studNo;                         //index for a student

// Open the grades file
   gradeFile.open( "a:\\grades.txt");
   if (!gradeFile)
   {
      cout << "Could not open \"grades.txt\"";
      return 1;
   }

// Get the semester test grades from the file
   GetGrades( gradeFile, grade, numStudents);

// Calculate the average grade for each test
   CalcClassAvg( grade, numStudents, classAvg);

// Calculate the test average for each student
   for (studNo = 0; studNo < numStudents; studNo++)
      CalcStudentAvg( grade[studNo], studentAvg[studNo]);

// Print test report
   PrintTests( grade, studentAvg, numStudents, classAvg);

   return 0;
}

//***************************************************************
//  Function: GetGrades
//
//  Purpose: Read test grades from a data file
//***************************************************************

void GetGrades( ifstream& gradeFile,  // in/out - input grade file
		int  grade[][4],       // out    - table of grades
		int& numStudents)        // out    - number of students
{                    
   int test1,        // Student's grade for test 1
       test2,        // Student's grade for test 2
       test3,        // Student's grade for test 3
       test4;        // Student's grade for test 4

   numStudents = 0;
   gradeFile >> test1 >> test2 >> test3 >> test4;
   while (gradeFile && numStudents < MAX_STUDENTS)
   {
      grade[numStudents][0] = test1;
      grade[numStudents][1] = test2;
      grade[numStudents][2] = test3;
      grade[numStudents][3] = test4;
      numStudents++;
      gradeFile >> test1 >> test2 >> test3 >> test4;
   }
}

//***************************************************************
//  Function: CalcClassAvg
//
//  Purpose: Calculate the class average for each test
//***************************************************************
                                             
void CalcClassAvg( const int grade[][4],  // in - table of grades
			 int numStudents, // in - number of students
		       float classAvg[])  // out - class avg on tests
{
   int studNo;     // Student index
   int testNo;     // Test index
   int sum;        // Sum of grades for a test

   for (testNo = 0; testNo < NUM_TESTS; testNo++)
   {
      sum = 0;
      for (studNo = 0; studNo < numStudents; studNo++)
      {
         sum += grade[studNo][testNo];
      }
      classAvg[testNo] = float (sum) / float(numStudents);
   }
}

//***************************************************************
//  Function: CalcStudentAvg
//
//  Purpose: Calculate the test average for one student
//***************************************************************
                                                      
void CalcStudentAvg( const int grade[], // in - test grades for one student
		     float& studentAvg) // out - student's test average
{
   int testNo;     // Test index
   int sum = 0;    // Sum of test grades for a student

   for (testNo = 0; testNo < NUM_TESTS; testNo++)
      sum+= grade[testNo];
   studentAvg = float (sum) / float (NUM_TESTS);
}

//***************************************************************
//  Function: PrintTests
//
//  Purpose: Print Test Report that includes all student test
//           grades, each student's test average, and the
//           class average for each test. 
//***************************************************************
                                                      
void PrintTests( const int grade[][4], // in - table of grades
		     float studentAvg[], // in - students test averages
		       int numStudents,  // in - number of students
		     float classAvg[])   // in - class avg for each test
{
   const int LINE_LENGTH = 60;

   int studNo;     // Student index
   int testNo;     // Test index
   int linePos;    // Position on a line

// Set up floating point formatting
   cout.setf( ios::fixed, ios::floatfield);
   cout.setf( ios::showpoint);
   cout << setprecision(1);

// Print report header
   cout << setw(10) << "Student No"
	<< setw(10) << "Test 1"
	<< setw(10) << "Test 2"
	<< setw(10) << "Test 3"
	<< setw(10) << "Test 4"
	<< setw(10) << "Test Avg"
	<< endl;
   for (linePos = 0; linePos < LINE_LENGTH; linePos++)
      cout << '=';
   cout << endl;

// Print grades for each student
   for (studNo = 0; studNo < numStudents; studNo++)
   {
      cout << setw(10) << studNo;
      for (testNo = 0; testNo < NUM_TESTS; testNo++)
	 cout << setw(10) << grade[studNo][testNo];
      cout << setw(10) << studentAvg[studNo]
           << endl;
   }

// Print class averages
   for (linePos = 0; linePos < LINE_LENGTH; linePos++)
      cout << '=';
   cout << endl;
   cout << setw(10) << "Class Avg ";
   for (testNo = 0; testNo < NUM_TESTS; testNo++)
      cout << setw(10) << classAvg[testNo];
   cout << endl;
}