/* Using logical operators to validate input */
#include <iostream>
using namespace std;

int main()
{
    int grade;
    cout << "Enter a numerical grade, and I will tell you" << endl;
    cout << "how well the student performed: ";
    cin >> grade;    // read an integer

    if (grade >= 0 && grade <= 100)
    {
        cout << "The student received a letter grade of ";
        if (grade >= 90 )
            cout << "A";
        else if (grade >= 80)
            cout << "B";
        else if (grade >= 70)
            cout << "C";
        else if (grade >= 60)
            cout << "D";
        else
            cout << "F";
        cout << "." << endl;
    }
    else
        cout << "The grade must be between 0 and 100." << endl;

    return 0;
}