#include <iostream>

using namespace std;

char IntToTrinaryDigit(int digit);
int  TrinaryToIntDigit(char digit);

int main() {
    char letter;
    int i;
    int value;

    for (letter = 'a'; letter <= 'z'; ++letter) {
        cout << "The letter " << letter << " is " << letter-'a' << " from a"
             << endl;
         
    }

    cout << endl << endl;

    for (i =0; i < 26; ++i) {
        cout << "The letter " << i << " characters from a is "
             <<  static_cast<char>('a'+i) << endl;
    }

    cout << endl << endl;

    for (letter = '0'; letter <= '9'; ++letter) {
        cout << "The character " << letter << " has an ascii value of " 
             << static_cast<int>(letter) << " and a numeric value of "
             << static_cast<int>(letter -'0') << endl;
    }

    cout << endl;
    cout << "Testing trinary conversions " << endl;

    for (i = -1; i < 4; ++i) {
        letter = IntToTrinaryDigit(i);
        value = TrinaryToIntDigit(letter);
        cout << i << " converts to '" << letter << "' and back to " 
             << value << endl;
    }

    return 0;
}

char IntToTrinaryDigit(int digit){
    char value{' '};
    if (digit >= 0 and digit < 3) {
       value = static_cast<char>('0' + digit);
    }
    return value;
}

int  TrinaryToIntDigit(char digit){
    int value{-1};
    if (digit >= '0' and digit < '3') {
       value = static_cast<int>(digit - '0');
    }
    return value;
}