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Given a dictionary scores with student names as keys and their scores as values, which code snippet safely retrieves the score for "John" without causing an error if the key is missing?

hard🚀 Application Q15 of Q15

C Sharp (C#) - Collections

Given a dictionary scores with student names as keys and their scores as values, which code snippet safely retrieves the score for "John" without causing an error if the key is missing?

Aint score = scores.ContainsKey("John");

Bint score = scores.GetValueOrDefault("John");

Cint score = scores["John"];

Dscores.TryGetValue("John", out int score);

Step-by-Step Solution

Solution:

Step 1: Understand safe retrieval methods
Using TryGetValue safely tries to get the value and returns false if key is missing without error.
Step 2: Analyze each option
int score = scores["John"]; throws an exception if "John" is missing. int score = scores.GetValueOrDefault("John"); is invalid in C# Dictionary (GetValueOrDefault is not standard). scores.TryGetValue("John", out int score); uses TryGetValue correctly. int score = scores.ContainsKey("John"); returns a boolean, not the score.
Final Answer:
scores.TryGetValue("John", out int score); -> Option D
Quick Check:
TryGetValue safely gets value [OK]

Quick Trick: Use TryGetValue to avoid errors on missing keys [OK]

Common Mistakes:

MISTAKES

Using indexer without checking key existence
Confusing ContainsKey with value retrieval
Expecting GetValueOrDefault method on Dictionary

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