3.7.3　foreach循环

foreach(type identifier in collection)
statement;

class TicTacToe       // Declares the TicTacToe class.
{
static void Main()  // Declares the entry point of the program.
{
// Hardcode initial board as follows
// ---+---+---
//  1 | 2 | 3
// ---+---+---
//  4 | 5 | 6
// ---+---+---
//  7 | 8 | 9
// ---+---+---
char[] cells = {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
};

      System.Console.Write(
"The available moves are as follows: ");

      // Write out the initial available moves
foreach (char cell in cells) 
{
if (cell != 'O' && cell != 'X')
{
System.Console.Write("{0} ", cell);
}  
} 
}
}

The available moves are as follows: 1 2 3 4 5 6 7 8 9

// ...

bool valid = false;

// Check the current player's input.
if( (input == "1") ||
(input == "2") ||
(input == "3") ||
(input == "4") ||
(input == "5") ||
(input == "6") ||
(input == "7") ||
(input == "8") ||
(input == "9") )
{
// Save/move as the player directed.
// ...

valid = true;
}
else if( (input == "") || (input == "quit") )
{
valid = true;
}
else
{
System.Console.WriteLine(
"\nERROR: Enter a value from 1-9. "
+ "Push ENTER to quit");
}

// ...