Difficulty: Easy
Correct Answer: s1 == s2
Explanation:
Introduction / Context:
Comparing strings in C#.NET can be done via operators or methods. Understanding which operator compares contents versus references is vital to avoid subtle bugs.
Given Data / Assumptions:
s1 and s2 are variables of type string.
Concept / Approach:
In C#, the == operator is overloaded for string to perform value (content) equality. Likewise, string.Equals compares contents (with overloads for comparison options). Assignment (=) does not compare; it overwrites references. The is operator tests type, not equality. C-style strcmp is not part of C#.
Step-by-Step Solution:
s1 == s2 → compares contents and returns a boolean.s1.Equals(s2) → also compares contents and returns a boolean (valid alternative).s1 = s2 → assignment, not comparison; wrong.s1 is s2 → type test, not equality; wrong.strcmp → not available in C#; wrong.
Verification / Alternative check:
To compare references (object identity), use Object.ReferenceEquals(s1, s2). That is different from content equality.
Why Other Options Are Wrong:
They either change the variable (=), test type (is), or use non-C# functions.
Common Pitfalls:
Mixing up content equality with reference equality; assuming == compares references for strings (in C#, it does content comparison).
Final Answer:
s1 == s2
Discussion & Comments