Exercise 1: Optional String with if let (Swift 5.7 Shorthand) — Possible Solution
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var favoriteColor: String? = nil

if let favoriteColor {
    print("Favorite color: \(favoriteColor)")
} else {
    print("No favorite color yet")
}
// Prints: No favorite color yet

favoriteColor = "Teal"

if let favoriteColor {
    print("Favorite color: \(favoriteColor)")
} else {
    print("No favorite color yet")
}
// Prints: Favorite color: Teal

HOW IT WORKS: favoriteColor is declared as String? (an optional
String), initially nil. The shorthand `if let favoriteColor { }`
(Swift 5.7, SE-0345) checks whether the optional currently holds a
real value - if it does, a new, non-optional constant with the same
name is available inside the block, holding that unwrapped value. If
the optional is nil, the `else` branch runs instead.

Re-running the same if-let block after assigning a real string to
favoriteColor demonstrates both real outcomes from the identical code,
just with the underlying value having changed between the two checks.

ANSWER: Declaring favoriteColor as String? = nil, then using
`if let favoriteColor { ... } else { ... }` correctly prints
"No favorite color yet" while nil, and "Favorite color: Teal" once
assigned - the same optional-binding code branches automatically based
on whether a real value is actually present.

WHY THIS WORKS AS AN ANSWER
------------------------------
This demonstrates the real Swift 5.7 if-let shorthand correctly
unwrapping an optional in both its nil and non-nil states, confirming
the same conditional logic handles both real cases without any
force-unwrapping.