C# 笔试题，看你会几道题

1.       Which interface you need to implement to support for each?

• • IEnumerator
  • IEnumerable
  • IComparer
  • IComparable
  • All of the above
  • None of the above

 

2.       What is the “internal” keyword used for?

• • To make a method to be used internally by the declaring class only.
  • To make a field that is accessed by multiple threads.
  • To use with the DllImport attribute when using Interop services to call into unmanaged code.
  • None of the above

 

3.       Read the following 2 statements about const and read-only field

• • A const field can only be initialised where it’s declared. A read-only field can be initialised where it’s declared or in a constructor.
  • A const field is set at compile time, but a read-only field is set at run time.

• 4.       Read the following statements about structs.
  • Structs are value types.
  • Structs are reference types.
  • Structs can be directly derived from System.Object.
  • Structs can be directly derived from System.ValueType.
  • Structs only allocate memory from stack.

• 5.       What is the keyword “delegate” used for?
  • Another visibility modifier like public, private, protected
  • Used in multi threaded programs to protect a variable
  • Used to define a method signature type that can be used as a typed variable
  • None of the above

• 6.       What is “boxing”?
  • Wrapping an object into a value type
  • Wrapping a value type into an object
  • Wrapping a collection into a byte array
  • None of the above

• 7.       Can I use “return” statement inside a “final” block?
  • Yes
  • No

• 8.       Is Delegate a type of Event?
  • Yes
  • No

• 9.       If x.Equals(y) is true. Is it correct that x.GetHashcode() != y.GetHashcode()?
  • Yes
  • No

• 10.   int keyword targets to which .Net type?
  1. System.Int8
  2. System.Int16
  3. System.Int32
  4. System.Int64