Which of the following correctly demonstrates nullable type syntax in C#?
Answer: A
The correct syntax for nullable types is 'type?' where ? makes the value type nullable, allowing null values.
Q.22Medium
Which access modifier provides access within the same assembly only?
Answer: C
'internal' modifier allows access within the same assembly but not from external assemblies.
Q.23Medium
How many dimensions does a jagged array have in the following declaration: int[][] arr;
Answer: B
int[][] is a two-dimensional jagged array where each element is an array of integers of potentially different lengths.
Q.24Medium
What is the correct way to check if a string is null or empty in modern C#?
Answer: D
Both methods work correctly. IsNullOrEmpty checks for null or empty, IsNullOrWhiteSpace also considers whitespace.
Q.25Medium
Which of the following statements about properties in C# is TRUE?
Answer: B
Properties can have get and set accessors independently with different access modifiers like public get, private set.
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Q.26Medium
What happens when you try to access an array element beyond its length in C#?
Answer: C
Accessing an array index beyond its bounds throws an IndexOutOfRangeException at runtime.
Q.27Medium
Which of the following demonstrates proper use of string interpolation in C# 6.0+?
Answer: A
String interpolation uses the $ prefix followed by curly braces containing expressions.
Q.28Medium
What will be the output of the following code? int x = 5; int y = ++x; Console.WriteLine(x + " " + y);
Answer: B
++x is pre-increment, so x becomes 6, then y is assigned 6. Both x and y are 6.
Q.29Medium
Which of the following correctly demonstrates the use of an out parameter in C#?
Answer: A
The 'out' keyword is used when a method needs to return a value through a parameter. The parameter must be assigned before the method exits.
Q.30Medium
What is the output of: bool result = (5 > 3) && (10 < 8); Console.WriteLine(result);
Answer: B
5 > 3 is true, but 10 < 8 is false. The && (AND) operator returns false because one condition is false.
Q.31Medium
Which collection type in C# automatically prevents duplicate values?
Answer: B
HashSet<T> is an unordered collection that automatically prevents duplicate values. List<T> allows duplicates.
Q.32Medium
In C#, what is the difference between '==' and 'Equals()' when comparing strings?
Answer: B
For strings in C#, '==' is overloaded to compare values, and Equals() also compares values. However, for other reference types, '==' compares references while Equals() compares values.
Q.33Medium
What is the correct way to create a generic method in C#?
Answer: A
Generic methods use angle brackets <T> after the method name. The syntax is: public void Method<T>() where T is the type parameter.
Q.34Medium
Which statement about anonymous functions in C# is TRUE?
Answer: B
Lambda expressions (introduced in C# 3.0) are a concise form of anonymous functions. They can infer return types and parameter types, and can access outer scope variables.
Q.35Medium
What is the output of: var x = 5; Console.WriteLine(x.GetType().Name);
Answer: B
The 'var' keyword declares a variable where the type is inferred at compile-time. Here, x is inferred as int, and GetType().Name returns 'Int32'.
Q.36Medium
Which of the following is a correct implementation of property with auto-backing field in C#?
Answer: A
Auto-properties with get; set; syntax automatically create backing fields. Option C is an expression-bodied property (read-only).
Q.37Medium
What will be the output of the following code? int a = 5; int b = ++a; Console.WriteLine(a + " " + b);
Answer: B
++a is pre-increment, which increments 'a' to 6 first, then assigns it to 'b'. So both a and b become 6. Output is '6 6'.
Q.38Medium
Which of the following correctly demonstrates string interpolation in C# 6.0 and above?
Answer: C
String interpolation uses the prefixwithcurlybracestoembedexpressions.OptionCshowsthecorrectsyntax:"Hello {name}". The @ symbol creates verbatim strings, not interpolated strings.
Q.39Medium
In C#, what is the difference between 'struct' and 'class'?
Answer: B
struct is a value type stored on the stack, while class is a reference type stored on the heap. struct does not support inheritance from other structs/classes (except interfaces), while classes do.
Q.40Medium
Which method is used to convert a string to an integer in C#?
Answer: D
Both int.Parse() and Convert.ToInt32() can convert strings to integers. int.TryParse() is safer as it returns a boolean indicating success/failure. All are valid approaches.
