Comma Quibbling
September 22, 2017
Eric Lippert, at his blog Fabulous Adventures in Coding, discusses the problem of comma quibbling, which turns a list of words like (“ABC” “DEF” “G” “H”) into the string “ABC, DEF, G and H” with commas between each pair of words except the last pair, which gets the word “and” (without a comma). Here are the rules:
- If the input is empty, so is the output.
- If the input has a single word, so does the output.
- If the input has two words, the output is the two words separated by “and”.
- If the input has more than two words, the output is all the words, separated by commas, but with the last comma replaced by “and”.
A word is a maximal sequence of characters not containing a comma or a space.
Your task is to write a function that adds commas to a list of words, using the rules described above. When you are finished, you are welcome to read or run a suggested solution, or to post your own solution or discuss the exercise in the comments below.
