面试题与答案

abstract, event, new, struct, explicit, null, base, extern, object, this

There are no access restrictions. All can access the public instance from anywhere.

Access is restricted to within the containing class.

Static.

No

using System;
namespace Console1
{
class Class1
{
[STAThread] // No longer needed
static void Main(string[] args)
{
Console.WriteLine("Hello world");
}
}
}

Recursion is when a method calls itself.

A constructor performs initialisation for an object (including the struct type) or class.

A C# destuctor is not like a C++ destructor. It is actually an override for Finalize(). This
is called when the garbage collector discovers that the object is unreachable. Finalize()
is called before any memory is reclaimed.

Bool, char, int, byte, double

Unicode

Any changes to that string are in fact copies.

trim, tolower, toupper, concat, copy, insert, equals, compare.

Converting a value type (stack->heap) to a reference type (heap->stack), and viseversa.

// Boxing
int i = 4;
object o = i;
// Unboxing
i = (int) o;

There are 2 kinds of heap � 1: a chunk of memory where data is stored and 2: a tree
based data structure. When we talk about the heap and the stack we mean the first kind
of heap. The stack is a LIFO data structure that stores variables and flow control
information. Typically each thread will have its own stack.

A pointer is a reference to a memory address.

Initializes an object.

Unlike in C++ a struct is not a class � it is a value type with certain restrictions. It is
usually best to use a struct to represent simple entities with a few variables. Like a Point
for example which contains variables x and y.

sbyte -128 to 127, byte 0 � 255, short -32,768 to 32,767, int -2,147,483,648 to
2,147,483,647, ulong 0 to 18,446,744,073,709,551,615

switch (n)
{
case 1:
x=1;
break;
case 2:
x=2;
break;
default:
goto case 1;
}