The Big Nerd Ranch Swift - Ch.20 Silver Challenge

There is no description of challenge. Becaouse of license.

When I use a header “class someName…” in code block for some code, that means the following code is within the scope of the class named ‘someName’.

First, We need position which is chracter’s index of stinrg. You want to add it the places where error would occur like InvalidCharacter. And we need to hold the position of invalid Character, so add it Tokens. I’ve implemented extra work that print caret(^) indicating position of invalid stuff intuitively.

This is a result image.

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