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Gilbert Joseph Smith III

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Details

• Difficulty: 2/5

Convert the given number into a roman numeral.

All roman numerals answers should be provided in upper-case.

Remember to use Read-Search-Ask if you get stuck. Try to pair program. Write your own code.

Useful Links

• Roman Numerals
• Array.splice()
• Array.indexOf()
• Array.join()

Problem Script:

function convert(num) {
 return num;
}

convert(36);

Problem Explanation:

• You will create a program that converts an integer to a roman numeral.

Hint: 1

• Creating an array with the Roman Numerals and one with the decimal equivalent for the new forms will be very helpful.

Hint: 2

• If you add the numbers that go before the new letter is introduce, it will save you plenty of code, like 4 and 9.

Hint: 3

• You can't have more than three consecutive Roman numerals together.

Spoiler Alert!

Solution ahead!

Code Solution:

var convert = function(num) {

  // Create arrays with default conversion with matching indices.
  var decimalValue = [1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000];
  var romanNumeral = ['I', 'IV', 'V', 'IX', 'X', 'XL', 'L', 'XC', 'C', 'CD', 'D', 'CM', 'M'];

  // Create a copy of num to work on and an empty string variable for the final roman number
  var numCopy = num;
  var romanized = '';

  // While the decimal number is greater than 0,
  while (numCopy > 0) {
    // Loop through the indices of the decimalValue array.
    for (var index = 0; index < decimalValue.length; index++) {
      // Get the maximum decimal number less or equal then the decimal number.
      if (+decimalValue[index] <= numCopy && +decimalValue[+index + 1] > numCopy) {
        // Add the Roman numeral & decrease numCopy by the decimal equivalent.
        romanized += romanNumeral[index];
        numCopy -= decimalValue[index];
      }
    }
  }

  return romanized;
};

Code Explanation:

• Read comments on code.