In C# the int value of char is the UTF-16 code, and ASCII codes is a subset of it.

replying to Jon - surely the int value of the character is the ASCII value?

Thank you for the answer! I have never used this before:)

Chars can be interpretted as arrays when doing arithmetic. Thus when you're attempting to sum digits as chars together, you're summing the integer value of the characters, not the actual digits. - '0' subtracts the int value of '0' from the int value of the character being popped, giving you the actual value you want as an integer.

Thank u for the answer!

but the description is "The input string will only consist of lower case letters and/or spaces"

That's true, thanks

Your for loop just need to check the other cards, not the first one anymore
I mean: for(int i=1; i<cards.Count(); i++)

Hey, why don't you delete all the space between lines in your code before you submit?