C# Programming - MCQ Practice Questions

++x is pre-increment. It increments x first (x becomes 6), then assigns the value to y. So both x and y are 6.

int is a value type (primitive type). string, object, and arrays are reference types in C#.

The 'const' keyword is used to declare constants in C#. 'final' is Java syntax. While 'readonly' can be used, 'const' is the proper keyword for compile-time constants.

For strings, '==' compares references (memory addresses) while Equals() compares the actual string values. However, C# has optimized string comparison, so both often behave similarly for string literals.

int.Parse() converts a string to an integer. Direct casting doesn't work for strings. Convert.ToInt32() would throw an exception if the string is not a valid number. The 'as' operator doesn't work for strings to primitives.

In C#, 'int?' is used to declare a nullable integer. A regular 'int' cannot be assigned null. int* is a pointer (unsafe code), not a nullable type.

(5 > 3) is true, but (2 < 1) is false. The '&&' (AND) operator returns true only if both conditions are true. Since one is false, the result is false.

'sealed' keyword prevents a class from being inherited in C#. 'final' is Java syntax. 'abstract' requires a class to be inherited. 'static' makes members class-level, not related to inheritance.

Accessing an array element beyond its bounds throws an IndexOutOfRangeException at runtime. This is a safety feature to prevent accessing invalid memory.

readonly keyword prevents reassignment of a field after initialization. const is for compile-time constants, static for class-level, sealed for inheritance prevention.

var is implicitly typed, meaning the compiler infers the type at compile time, but it's still strongly typed. It's not dynamic.

Accessing array elements beyond bounds throws IndexOutOfRangeException at runtime.

x++ is post-increment, so it returns the current value (5) before incrementing. The next Console.WriteLine would print 6.

Abstract classes can contain both abstract and non-abstract (concrete) methods and properties. They cannot be instantiated directly.

protected members are accessible from the same class and derived classes, but not from outside the class hierarchy.

C# allows comparison between int and double. 5 and 5.0 are numerically equal, so == returns True.

Jagged arrays use [][] syntax. [,] is for multidimensional arrays. int[][] allows arrays of varying lengths.

using serves two purposes: importing namespaces and automatically disposing resources through IDisposable pattern.

int is a value type. When y = x, a copy of x's value is assigned to y. Changing y doesn't affect x.

sbyte range is -128 to 127. When overflow occurs without checked context, it wraps around to 127.