[Solved] Find the mistake in this code snippet:var dict = ["x": 10] var copy = dict copy["y"] = 20 print(dict["y"]!) | Swift

Swift - Collections

Find the mistake in this code snippet:

var dict = ["x": 10]
var copy = dict
copy["y"] = 20
print(dict["y"]!)

AMissing type annotation for dictionary

BDictionaries cannot be copied in Swift

CAccessing a key that does not exist causes a runtime error

DCannot assign new keys to copied dictionary

Step-by-Step Solution

Solution:

Step 1: Understand dictionary copy behavior
Copying creates a new dictionary; adding "y" to copy does not add it to original.
Step 2: Check print statement
Accessing dict["y"] fails because "y" is not a key in original dict, causing runtime error.
Final Answer:
Accessing a key that does not exist causes a runtime error -> Option C
Quick Check:
Accessing missing keys causes error [OK]

Quick Trick: Check keys exist before force unwrapping dictionary values [OK]

Common Mistakes:

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