C# 0 The Complete Reference

PART I

C h a p t e r   1 9 :  

L I N Q  

561

PART IPART I

B Z

C X

C Y

C Z

The program begins by creating a class called 

ChrPair

 that will hold the results of the 

query. It then creates two character arrays, called 

chrs

 and 

chrs2

. It uses the following query 

to produce all possible combinations of the two sequences:

var pairs = from ch1 in chrs

              from ch2 in chrs2

              select new ChrPair(ch1, ch2);

The nested 

from

 clauses cause both 

chrs

 and 

chrs2

 to be iterated over. Here is how it works. 

First, a character is obtained from 

chrs

 and stored in 

ch1

. Then, the 

chrs2

 array is enumerated. 

With each iteration of the inner 

from

, a character from 

chrs2

 is stored in 

ch2

 and the 

select

clause is executed. The result of the 

select

 clause is a new object of type 

ChrPair

 that contains 

the character pair