Determine the result of code segments
Learning Objective: Evaluate expressions that manipulate strings
String concatenation joins together two or more strings end-to-end to make a new string.
AAP-2.D.2
A substring is part of an existing string
https://www.albert.io/learn/ap-computer-science-principles/34-strings/using-substring-1-of-3-jmdba
https://www.khanacademy.org/computing/ap-computer-science-principles/programming-101/strings/a/storing-strings-in-variables
https://library.fiveable.me/ap-comp-sci-p/big-idea-3/strings/study-guide/0bMtDyDHxqMcwyDgQkjw#:~:text=What%20are%20Strings%3F,you%20can%20still%20manipulate%20them.