function romanNumeral(number) {
    var input = number;
    var romSinglesChar, romFourChar, romFivesChar, romTensChar, romHundredsChar = '';
    var romanNumeral = [];
    //minimal input validation
    if (input > 1000) {
        console.log("input over limit");
        return;
    }
    //reverse the String
    var reversedInput = input.split("").reverse().join("");
    //console.log(reversedInput);
    //process one digit at a time
    for (index = 1; index <= reversedInput.length; index++) {
        if (reversedInput.length <= 4) {
            var digit = reversedInput[index - 1];
            //calculate the max: 1000
            if (digit == "1" && index == 4) {
                romanNumeral.push("M");
            }
            //calculate 999 and below
            switch (digit) {
                //0
                case "0":
                    break;
                    //1-3
                case "1":
                case "2":
                case "3":
                    romSinglesChar = getRomanSinglesChar(index);
                    for (i = 1; i <= parseInt(digit); i++) {
                        romanNumeral.push(romSinglesChar);
                    }
                    break;
                    //4
                case "4":
                    romFourChar = getRomanFourChar(index);
                    romanNumeral.push(romFourChar);
                    break;
                    //5
                case "5":
                    romFivesChar = getRomanFivesChar(index);
                    romanNumeral.push(romFivesChar);
                    break;
                    //6-8
                case "6":
                case "7":
                case "8":
                    for (i = 1; i <= parseInt(digit) - 5; i++) {
                        romanNumeral.push(getRomanSinglesChar(index));
                    }
                    romanNumeral.push('V');
                    break;
                    //9
                case "9":
                    romanNumeral.push(getRomanNinesChar(index))
                    break;
            }
        }
    }
    return romanNumeral.reverse().toString().split(",").join("");
}
//output 1s
function getRomanSinglesChar(index) {
    switch (index) {
        case 1:
            return "I";
        case 2:
            return "X";
        case 3:
            return "C";
    }
}
//output 4s
function getRomanFourChar(index) {
    switch (index) {
        case 1:
            return "IV";
        case 2:
            return "XL";
        case 3:
            return "CD";
    }
}
//output 5s
function getRomanFivesChar(index) {
    switch (index) {
        case 1:
            return 'V';
        case 2:
            return 'L';
        case 3:
            return 'D';
    }
}
//output 9s
function getRomanNinesChar(index) {
    switch (index) {
        case 1:
            return "IX";
        case 2:
            return "XC";
        case 3:
            return "CM";
    }
}