Convert Roman numerals to decimal

Hi everybody:

 

I am new to C# world and I was trying to solve this problem.

 

Convert roman number to decimal. I am just trying to limit it to 500 i.e. M in Roman number. I have referred to many other blogs and sites but most of them are either not clear or not explained properly or I am having hard time understanding.

 

Assumption is: 1. user enters roman character

2. the roman character is converted to decimal. case doesn't matter, also space doesn't matter.  

 

If anybody has a good way to express the algorithm or code in C#, I would really appreciate.

 

At  the mean time, I will be trying on my end to solve it as well.

 

Thank you.