Copying the contents of one string to another in C#.NET: choose the statement that correctly creates a new string with the same contents as an existing one.
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AString s1 = 'String';\nString s2; \ns2 = s1;
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BString s1 = 'String' ; \nString s2;\ns2 = String.Concat(s1, s2);
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CString s1 = 'String'; \nString s2;\ns2 = String.Copy(s1);
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DString s1 = 'String'; \nString s2;\ns2 = s1.Replace();
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EString s1 = 'String'; \nString s2;\ns2 = s2.StringCopy(s1);
Answer
Correct Answer: String s1 = 'String'; \nString s2;\ns2 = String.Copy(s1);
Explanation
Introduction / Context:Copying strings can mean either copying the reference (two variables refer to the same instance) or creating a distinct string object with the same contents. This question targets creating a separate string instance with identical content.
Given Data / Assumptions:
- We want to 'copy the contents' of one string into another.
- Options include assignment,
String.Concat,String.Copy, and invalid usages.
Concept / Approach:Assignment (s2 = s1) copies the reference, not the object; both variables point to the same immutable instance. String.Copy(s1) historically created a new string instance with the same content (note: it is obsolete in newer .NET, but within classic C#.NET contexts, it denotes a content copy). Concat concatenates and does not copy content alone. Replace() without arguments is invalid, and StringCopy is not an API.
Step-by-Step Solution:
Option A: Reference copy only (same instance) → not a distinct content copy.Option B: Concatenatess1 and s2 (undefined s2 content) → incorrect.Option C: String.Copy(s1) → creates a new string with the same contents.Option D: Invalid method usage.Option E: Nonexistent method.Verification / Alternative check:Another way to ensure a distinct instance is new string(s1.ToCharArray()), though rarely necessary. Since strings are immutable, reference sharing is usually safe.
Why Other Options Are Wrong:They either do not produce a new object with the same contents or call invalid/nonexistent APIs.
Common Pitfalls:Assuming assignment duplicates the object; in .NET it only assigns the reference.
Final Answer:String s1 = 'String'; String s2;s2 = String.Copy(s1);