Explanation:

The function takes in a single parameter, "num", which is the number to be converted to Roman numerals.

The variable "roman" is initialized as an empty string. This variable will be used to store the Roman numeral representation of "num".

The variable "romanNumeral" is an array of strings, containing the Roman numerals in the order they are to be used in the conversion.

The variable "numbers" is an array of integers, containing the decimal equivalents of the Roman numerals in "romanNumeral"

The function uses a for loop to iterate through the "numbers" array.

Within the for loop, the function uses a while loop to check if the current number in "numbers" is less than or equal to the value of "num". If this is the case, the corresponding Roman numeral from "romanNumeral" is added to "roman", and the value of "num" is reduced by the current number in "numbers".

Once the for loop completes execution, the function returns the final value of "roman", which is the Roman numeral representation of the input number "num".

Explanation:

The function takes in a single parameter, "s", which is the Roman numeral to be converted to a number.

The variable "roman" is an object which has Roman numerals as key and their integer value as value.

The variable "result" is initialized as 0. This variable will be used to store the integer representation of "s".

The function uses a for loop to iterate through the characters of "s".

Within the for loop, the function uses the object "roman" to get the integer value of current character and next character.

If the next character has a greater value than the current character, it means the current character is used as a subtractive notation in the Roman numeral and it should be subtracted from the result. Else it should be added to the result.

Once the for loop completes execution, the function returns the final value of "result", which is the integer representation of the input Roman numeral "s".

The code snippet also has a test case where it calls the function and pass a Roman numeral "III" as an argument, and the output should be 3.