Can anyone give me somewhere to start if I have to convert from Roman Numeral to decimals? M - 1000 D - 500 C - 100 L - 50 X - 10 V - 5 I - 1 that if the user inputs CD - 400 MD - 1500 IX - 9 MXIII - 1013 I just need a rough guide on how to do this. All I know is if the digit's value before is smaller, then subtracts and if not, just keep adding. any example would help me greatly. thanks. PS: how do I also make the scanf determine the number of letters input?