Class Exercise Solution

#include <iostream.h>
#include <fstream.h>
#include <string.h>
#include <iomanip.h>

class student{
public:
	enum grade{A, B, C, D, F};
	student(char* ,float ,float );
	~student();
	void print();
private:
	void compute_total();
	char *student_id;
	float exam1;
	float exam2;
	float total;
	grade letter_grade;
};

student::student(char* sid, float ex1, float ex2) : exam1(ex1),
exam2(ex2){
	student_id = new char[strlen(sid)+1];
	strcpy(student_id, sid);
	compute_total();
}

student::~student(){
	delete [] student_id;
}

void student::compute_total(){
	total = exam1+exam2;
	const float grade_array[] = {90.0, 75.0, 60.0, 50.0};
	for(int i=0; i<4; i++){
		if(total >= grade_array[i]) break;
	}

	switch(i){
		case 0:	 letter_grade = A;
			 break;
		case 1:	 letter_grade = B;
			 break;
		case 2:	 letter_grade = C;
			 break;
		case 3:	 letter_grade = D;
			 break;
		default: letter_grade = F;
			 break;
	}
}

void student::print(){
	char grade;
	switch(letter_grade){
		case A: grade = 'A';
			break;
		case B: grade = 'B';
			break;
		case C: grade = 'C';
			break;
		case D: grade = 'D';
			break;
		case F: grade = 'F';
			break;
	}

	cout.setf(ios::fixed | ios::left);
	cout.precision(2);
	cout << setw(20) << "Student ID" << setw(9) << "Exam 1";
	cout << setw(9) << "Exam 2" << setw(9) << "Total";
	cout << setw(9) << "Grade" << endl;
	cout << setw(20) << student_id << setw(9) << exam1;
	cout << setw(9) << exam2 << setw(9) << total;
	cout << setw(9) << grade << endl;
}			

int main(){

	char id[8];
	float ex1, ex2;
	student* studentptr[3];
	ifstream fin("grades.dat");

	fin >> id >> ex1 >> ex2;
	for (int i=0; !fin.eof(); i++){
		studentptr[i] = new student(id, ex1, ex2);
		fin >> id >> ex1 >> ex2;
	}

	for (int j=0; j < 3; j++){
		studentptr[j]->print();
	}

	for (j=0; j < 3; j++){
		delete studentptr[j];
	}

	return(0);
}

Output:
Student ID          Exam 1   Exam 2   Total    Grade    
s999999             45.00    50.00    95.00    A
Student ID          Exam 1   Exam 2   Total    Grade    
s888888             40.00    42.00    82.00    B
Student ID          Exam 1   Exam 2   Total    Grade    
s777777             47.00    22.00    69.00    C