//-----------------------------------------------
// LetterGrade.cpp
//
// Illustrate nested if-then-else structure.
// Given a test score, determine the letter
// grade.
//
// D. Searls
// Asbury College
// Sept. 2006
//-----------------------------------------------

#include<iostream>

using namespace std;

char letterGrade(int score);

int main()
{
    int testScore;
    
    cout << "Enter test score (0 - 100): ";
    cin >> testScore;
    while (testScore < 0 || testScore > 100)
    {
        if (testScore < 0)
        {
            cout << "You entered a negative test score." << endl;
        }
        else
        {
            cout << "You entered a score greater than 100." << endl;
        }
        cout << "Enter test score (0 - 100): ";
        cin >> testScore;
    }

    cout << endl
         << "A score of " << testScore
         << " corresponds to a grade of " << letterGrade(testScore) << "."
         << endl;
         
    return 0;
}

//-----------------------------------------------
// letterGrade
//
// Given a test score in the range 0 to 100, this
// function returns the corresponding letter
// grade.
//
// Pre-condition: 0 <= score <= 100
//
// In Parameter: score
//-----------------------------------------------
char letterGrade(int score)
{
    char grade;
    
    if (score >= 90)
    {
        grade = 'A';
    }
    else if (score >= 80)
    {
        grade = 'B';
    }
    else if (score >= 70)
    {
        grade = 'C';
    }
    else if (score >= 60)
    {
        grade = 'D';
    }
    else
    {
        grade = 'F';
    }
    
    return grade;
}