C# 0 The Complete Reference

int

 array called 

n

. Then, 

this array is cycled through from back to front. In the process, each integer value in 

n

 is 

used as an index into 

digits

, with the corresponding string being displayed.

Strings Are Immutable

Here is something that might surprise you: The contents of a 

string

 object are immutable. 

That is, once created, the character sequence comprising that string cannot be altered. This 

restriction allows strings to be implemented more efficiently. Even though this probably 

sounds like a serious drawback, it isn’t. When you need a string that is a variation on one 

that already exists, simply create a new string that contains the desired changes. Since 

unused string objects are automatically garbage-collected, you don’t even need to worry 

about what happens to the discarded strings.

It must be made clear, however, that 

string

 reference variables may, of course, change 

which object they refer to. It is just that the contents of a specific 

string

 object cannot be 

changed after it is created.

To fully understand why immutable strings are not a hindrance, we will use another of