CS-111: College Grade calculation

grade.cpp

/* Copyright 2019 (c) Ralph Wilson Aguilar
 * For CS-111
 * Do not copy or redistribute without permission
 */
#include <iostream>

using namespace std;


// This is based on the Philippine College Grading System.
// To calculate the score we subtract minimum to the difference of minimum subtracted to the points.
// then divide it against the quantity of the total change in score divided by the total change in points.
//
// See: https://www.scholaro.com/pro/countries/Philippines/Grading-System
double getGrade(double points)
{
    if (points < 70) return 5;
    if (points < 75) return 5 - (points - 70) / 5;
    if (points < 77) return 4 - (points - 75) / 2;
    if (points < 89) return 3 - (points - 77) / 12;
    if (points < 91) return 2 - (points - 89) / 8;
    if (points < 94) return 1.75 - (points - 91) / 12;
    if (points < 96) return 1.5 - (points - 94) / 8;
    return 1.25 - (points - 96) /16;
}

// Same energy as above but we define this range to print the grade status.
// Its easier to read what the integer meant according to some people.
auto printGradeStatus(double points)
{
    if (points < 70) return "Conditional/Failed";
    if (points < 75) return "Passing - Below Average";
    if (points < 77) return "Passing - Average";
    if (points < 89) return "Passing - Above Average";
    if (points < 94) return "Above Average";

    // now you may wonder why there's a default one here? This is for anything 96 and above.
    // catch my drift?
    return "Excellent";
}

int main ()
{
    double gradeInput;

    cout << "Enter your grade in percent (without the %): ";
    cin >> gradeInput;

    if (gradeInput > 100)
    {
        cout << "Illegal input. Exiting.\n";
        return 1;
    }

    // we store getGrade's value in a var so we can compare
    // it to certain heuristics.
    double gradeOutput = getGrade(gradeInput);

    // printf is the only sane way to print out decimals in the first 2 decimal places.
    printf("Your grade is : %.2f \n", gradeOutput);
    cout << "This grade is " << printGradeStatus(gradeInput) << endl;

    return 0;
}