I can't speak about C, but I imagine that it is similar process to Visual Basic or HyperCard.
Roman numerals are not "place dependent" so you need to write a repeating loop which will cycle through the individual characters of the string and add their value to a variable, 100 for C, 10 for X and so on, and at the end of the loop display the variable. Start the variable with a value of 0 and then it will increase as you process each character.
-----
Not strictly true, as using the above method IV would give 6 instead of 4.
You would need to loop from right to left, adding up the individual characters.
But if an individual character has a lower value than the character to its right, you would need to subtract instead of add.
e.g.
XIV = 5 - 1 + 10 = 14
MCM = 1000 - 100 + 1000 = 1900
XVII = 1 + 1 + 5 + 10 = 17
no you dumbo, roman numerals cannot have decimal
128
Roman numerals MXC are the equivalent of the decimal number 1090
It is 0.024
In Roman numerals, it means XLVIII. In decimal notation, it means 48.
no you dumbo, roman numerals cannot have decimal
128
Fraction to decimal number conversion calculator, how to convert and conversion table. ... Expand the denominator to be a power of 10.
It is 0.024
81000.00
It is 0.005
That is 31 in decimal
Roman numerals MXC are the equivalent of the decimal number 1090
2723
It is 0.024
The number is already in decimal form: no conversion is required.
In Roman numerals, it means XLVIII. In decimal notation, it means 48.