/* GPA program (translated from C to C++)
  gpa.in contains sample input
  gpa.out contains sample output
  In order to use them with this program, you must use file I/O redirection in Unix
*/

#include <iostream>
#include <string>
#include <cstdio>

using std::cout;
using std::cin;
using std::endl;
using std::string;

// function declarations = prototypes
double getpoints(string &);  // no param names needed

int main(void)
{
    string grade;
    double credits;
    double points;
    double totalpoints = 0, totalcredits = 0;

    cout << "enter grades and credits: " << endl;

    // repeat until end of input
    while (cin >> grade >> credits) {

        points = getpoints(grade);
		totalpoints += points * credits;
		totalcredits += credits;
        printf("grade is: %-2s credits = %4f points = %4.1f \n", grade.c_str(), credits, points);
    } // while not EOF

	cout.precision(3);
	cout << "GPA is " << totalpoints / totalcredits << endl;
	return 0;  // 0 means no errors
} // main

double getpoints(string& g)
{
    double points = 0;
    g[0] = toupper(g[0]);
    switch (g[0]) {
    case 'A': points = 4; break;
    case 'B': points = 3; break;
    case 'C': points = 2; break;
    case 'D': points = 1; break;
    default: points = 0;
    }

	if (g.size() > 1) {
    if (g.at(1) == '+' && 'B' <= g[0] && g[0] <= 'D')
        points += .3;
    if (g.at(1) == '-' && 'A' <= g[0] && g[0] <= 'C')
        points -= .3;
	}
    return points;
}