You have an optional string var input: String? = nil. You want to print its value only if it exists, otherwise print "No input". Which code safely achieves this without crashing?

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Swift - Optionals

You have an optional string var input: String? = nil. You want to print its value only if it exists, otherwise print "No input". Which code safely achieves this without crashing?

Aprint(input!)

Bprint(input ?? "No input")

Cprint(input!) ?? "No input"

Dprint(input != nil ? input! : nil)

Step-by-Step Solution

Solution:

Step 1: Understand the goal
Print the value if it exists; otherwise print "No input" safely without crash.
Step 2: Analyze options
print(input ?? "No input") uses nil-coalescing operator ?? to provide default string if input is nil, avoiding force unwrap crash.
Final Answer:
print(input ?? "No input") -> Option B
Quick Check:
Use ?? to safely unwrap or default [OK]

Quick Trick: Use ?? to provide default instead of force unwrap [OK]

Common Mistakes:

Force unwrapping nil causing crash
Misusing ?? with force unwrap
Printing nil instead of default string

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More Swift Quizzes

You have an optional string var input: String? = nil. You want to print its value only if it exists, otherwise print "No input". Which code safely achieves this without crashing?

Step 1: Understand the goal

Step 2: Analyze options

Final Answer:

Quick Check:

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