Comparing string contents in C#.NET: which of the following are valid ways to determine if two strings s1 and s2 have equal contents? 1) if(s1 = s2) 2) if(s1 == s2) 3) int c; c = s1.CompareTo(s2); 4) if(strcmp(s1, s2)) 5) if (s1 is s2)

Introduction / Context:
This problem focuses on correct techniques for string equality checks in C#.NET. Understanding operators and methods available in the .NET framework helps avoid logic errors.

Given Data / Assumptions:

• We have two string references s1 and s2.
• We want to know whether their contents are equal.

Concept / Approach:
In C#, the == operator is overloaded for string to perform content comparison. CompareTo returns 0 when two strings are equal. C-style strcmp is not a C# function. The is operator checks type compatibility, not content equality. Assignment (=) is not a comparison.

Step-by-Step Solution:

Verification / Alternative check:
Using s1.Equals(s2) is another standard approach that returns a boolean, with overloads for culture and case options.

Why Other Options Are Wrong:
They include non-C# functions, type checks, or misuse assignment.

Common Pitfalls:
Forgetting to compare CompareTo’s result to zero, and confusing identity vs. equality.

Final Answer:
2, 3