C# Programming - MCQ Practice Questions

Auto-properties with get; set; syntax automatically create backing fields. Option C is an expression-bodied property (read-only).

The 'using' statement ensures that Dispose() is called on objects implementing IDisposable, preventing resource leaks. Importing namespaces is a different use of 'using'.

The null-coalescing operator (??) returns the right operand if the left is null. Since text is null, it prints 'Default'.

Method overloading requires same method name but different parameter types, count, or order. Return type alone is insufficient for overloading.

Post-increment (x++) returns the current value before incrementing. So y = 10, then x becomes 11. Output is '11, 10'.

The 'const' keyword declares a constant whose value cannot be modified. Both 'const' and 'readonly' prevent changes, but 'const' is compile-time constant while 'readonly' is runtime constant.

The default access modifier for class members in C# is 'private'. This means the member is only accessible within the same class unless explicitly specified otherwise.

Value types (int, double, struct, etc.) are stored on the stack memory. Reference types (class, interface) are stored on the heap. Value types don't require null checks like reference types.

++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'.

String interpolation uses the $prefixwithcurlybracestoembedexpressions.OptionCshowsthecorrectsyntax:$"Hello {name}". The @ symbol creates verbatim strings, not interpolated strings.

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.

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.

The && operator requires both conditions to be true. (5 > 3) is true, but (3 < 2) is false. Since one condition is false, the entire expression evaluates to false.

Both int? and Nullable<int> represent the same nullable integer type. int? is the shorthand syntax for Nullable<int>. They allow the variable to hold a null value in addition to integer values.

'params' allows a method to accept a variable number of arguments of the same type as an array. For example: void Method(params int[] numbers) can accept 0 or more integers.

In C#, the == operator for strings compares their values, not references. Since both s1 and s2 contain "Hello", the result is true. This is different from object references comparison.

List<T> maintains insertion order and allows duplicates. HashSet<T> doesn't allow duplicates. Dictionary<K,V> maintains key-value pairs. SortedSet<T> keeps elements sorted without duplicates.

'abstract' keyword creates a class that serves as a blueprint for derived classes and cannot be instantiated directly. Abstract classes can contain abstract methods that must be implemented by derived classes.

C# implements multiple interface inheritance by listing interfaces separated by commas after the class name: class MyClass : Interface1, Interface2. There is no 'extends' or 'implements' keyword in C#.

The GetType().Name returns the type name as "Decimal" (capitalized). The 'm' suffix specifies a decimal literal. The output shows the CLR type name, which is "Decimal".