https://stackoverflow.com/questions/22732857
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RussianYou need to instantiate the class:
ThreeD boardOne = new ThreeD();
ThreeD boardTwo = new ThreeD();
ThreeD boardThree = new ThreeD();
If you don't do this you cannot access the non-static class members.
C# use of unassigned variable?
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23-06-2023 - |
سؤال
So basically I have a class for a TicTacToe game and a derived class just to practice using inheritance. The class has several methods and all should work perfectly fine but in the main function, when I finally make three objects of the derived class I get three errors "use of unassigned local variable 'boardOne'" "use of unassigned local variable 'boardTwo'" and "use of unassigned local variable 'boardThree'". I do not understand why this is, they are objects, not variables.
public class TicTacToe
{
protected char[] boardCells = new char[9];
public int boardSpacesUsed;
public TicTacToe() //constructor
{
boardCells[0] = '1';
boardCells[1] = '2';
boardCells[2] = '3';
boardCells[3] = '4';
boardCells[4] = '5';
boardCells[5] = '6';
boardCells[6] = '7';
boardCells[7] = '8';
boardCells[8] = '9';
boardCells[9] = '\0';
int boardSpacesUsed = 0;
}
public void playerOneMove()
{
bool space = false;
char cell = '\0';
while (space == false)
{
Console.WriteLine("Please enter cell number you wish to mark: ");
cell = Convert.ToChar(Console.ReadLine());
switch (cell)
{
case '1':
if (boardCells[0] == 'X' || boardCells[0] == 'O')
{
Console.WriteLine("Illegal Move");
}
else
{
boardCells[0] = 'X';
space = true;
}
break;
case '2':
if (boardCells[1] == 'X' || boardCells[1] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[1] = 'X';
space = true;
}
break;
case '3':
if (boardCells[2] == 'X' || boardCells[2] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[2] = 'X';
space = true;
}
break;
case '4':
if (boardCells[3] == 'X' || boardCells[3] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[3] = 'X';
space = true;
}
break;
case '5':
if (boardCells[4] == 'X' || boardCells[4] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[4] = 'X';
space = true;
}
break;
case '6':
if (boardCells[5] == 'X' || boardCells[5] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[5] = 'X';
space = true;
}
break;
case '7':
if (boardCells[6] == 'X' || boardCells[6] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[6] = 'X';
space = true;
}
break;
case '8':
if (boardCells[7] == 'X' || boardCells[7] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[7] = 'X';
space = true;
}
break;
case '9':
if (boardCells[8] == 'X' || boardCells[8] == 'O')
Console.WriteLine("Illegal Move");
else
{
boardCells[8] = 'X';
space = true;
}
break;
default:
Console.WriteLine("Cell Does NOT Exist!");
break;
}// end of switch statement
}//end of while loop
boardSpacesUsed++;
}// end of playerOneMove();
public void CPUMove() //method marks cell for CPU
{
int iCell = 0;
bool space = false;
while (space == false)
{
Random rand = new Random();
iCell = rand.Next(1, 9);
switch (iCell) //switch statement to mark the cell
{
case 1:
if (boardCells[0] == 'X' || boardCells[0] == 'O')
{
space = false;
}
else
{
boardCells[0] = 'O';
space = true;
}
break;
case 2:
if (boardCells[1] == 'X' || boardCells[1] == 'O')
space = false;
else
{
boardCells[1] = 'O';
space = true;
}
break;
case 3:
if (boardCells[2] == 'X' || boardCells[2] == 'O')
space = false;
else
{
boardCells[2] = 'O';
space = true;
}
break;
case 4:
if (boardCells[3] == 'X' || boardCells[3] == 'O')
space = false;
else
{
boardCells[3] = 'O';
space = true;
}
break;
case 5:
if (boardCells[4] == 'X' || boardCells[4] == 'O')
space = false;
else
{
boardCells[4] = 'O';
space = true;
}
break;
case 6:
if (boardCells[5] == 'X' || boardCells[5] == 'O')
space = false;
else
{
boardCells[5] = 'O';
space = true;
}
break;
case 7:
if (boardCells[6] == 'X' || boardCells[6] == 'O')
space = false;
else
{
boardCells[6] = 'O';
space = true;
}
break;
case 8:
if (boardCells[7] == 'X' || boardCells[7] == 'O')
space = false;
else
{
boardCells[7] = 'O';
space = true;
}
break;
case 9:
if (boardCells[8] == 'X' || boardCells[8] == 'O')
space = false;
else
{
boardCells[8] = 'O';
space = true;
}
break;
}
}
boardSpacesUsed++;
}
public void getBoardCells()
{
Console.WriteLine(" " + " " + " | " + " " + " | " + " ");
Console.WriteLine(" " + boardCells[0] + " | " + boardCells[1] + " | " + boardCells[2]);
Console.WriteLine("__" + "_" + "__|__" + "_" + "__|__" + "_");
Console.WriteLine(" " + " " + " | " + " " + " | " + " ");
Console.WriteLine(" " + boardCells[3] + " | " + boardCells[4] + " | " + boardCells[5]);
Console.WriteLine("__" + "_" + "__|__" + "_" + "__|__" + "_");
Console.WriteLine(" " + " " + " | " + " " + " | " + " ");
Console.WriteLine(" " + boardCells[6] + " | " + boardCells[7] + " | " + boardCells[8]);
Console.WriteLine(" " + " " + " | " + " " + " | " + " ");
}
public bool playerOneWinCheck(ref int score)
{
bool check = false;
if (boardCells[0] == 'X' && boardCells[1] == 'X' && boardCells[2] == 'X')
{
check = true;
score++;
}
if (boardCells[3] == 'X' && boardCells[4] == 'X' && boardCells[5] == 'X')
{
check = true;
score++;
}
if (boardCells[6] == 'X' && boardCells[7] == 'X' && boardCells[8] == 'X')
{
check = true;
score++;
}
if (boardCells[0] == 'X' && boardCells[3] == 'X' && boardCells[6] == 'X')
{
check = true;
score++;
}
if (boardCells[1] == 'X' && boardCells[4] == 'X' && boardCells[7] == 'X')
{
check = true;
score++;
}
if (boardCells[2] == 'X' && boardCells[5] == 'X' && boardCells[8] == 'X')
{
check = true;
score++;
}
if (boardCells[0] == 'X' && boardCells[4] == 'X' && boardCells[8] == 'X')
{
check = true;
score++;
}
if (boardCells[6] == 'X' && boardCells[4] == 'X' && boardCells[2] == 'X')
{
check = true;
score++;
}
if (check == true)
return true;
else
return false;
}
public bool CPUWinCheck(ref int score) //Method to check to see if CPU won INCRAMENTS SCORE UP ONE IF ANYTHING HOLDS TRUE
{
bool check = false;
if (boardCells[0] == 'O' && boardCells[1] == 'O' && boardCells[2] == 'O')
{
check = true;
score++;
}
if (boardCells[3] == 'O' && boardCells[4] == 'O' && boardCells[5] == 'O')
{
check = true;
score++;
}
if (boardCells[6] == 'O' && boardCells[7] == 'O' && boardCells[8] == 'O')
{
check = true;
score++;
}
if (boardCells[0] == 'O' && boardCells[3] == 'O' && boardCells[6] == 'O')
{
check = true;
score++;
}
if (boardCells[1] == 'O' && boardCells[4] == 'O' && boardCells[7] == 'O')
{
check = true;
score++;
}
if (boardCells[2] == 'O' && boardCells[5] == 'O' && boardCells[8] == 'O')
{
check = true;
score++;
}
if (boardCells[0] == 'O' && boardCells[4] == 'O' && boardCells[8] == 'O')
{
check = true;
score++;
}
if (boardCells[6] == 'O' && boardCells[4] == 'O' && boardCells[2] == 'O')
{
check = true;
score++;
}
if (check == true)
return true;
else
return false;
}
~TicTacToe()
{
for (int c = 0; c <= 10; c++)
{
boardCells[c] = '\0';
}
boardSpacesUsed = 0;
}
}
public class ThreeD : TicTacToe
{
public void threeDWinCheck(ThreeD boardOne, ThreeD boardTwo, ThreeD boardThree, ref int score) //new function to check to see ThreeD wins
{
if (boardOne.boardCells[0] == 'X' && boardTwo.boardCells[0] == 'X' && boardThree.boardCells[0] == 'X')
{
score++;
Console.WriteLine("did it make it");
}
if (boardOne.boardCells[1] == 'X' && boardTwo.boardCells[1] == 'X' && boardThree.boardCells[1] == 'X')
score++;
if (boardOne.boardCells[2] == 'X' && boardTwo.boardCells[2] == 'X' && boardThree.boardCells[2] == 'X')
score++;
if (boardOne.boardCells[3] == 'X' && boardTwo.boardCells[3] == 'X' && boardThree.boardCells[3] == 'X')
score++;
if (boardOne.boardCells[4] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[4] == 'X')
score++;
if (boardOne.boardCells[5] == 'X' && boardTwo.boardCells[5] == 'X' && boardThree.boardCells[5] == 'X')
score++;
if (boardOne.boardCells[6] == 'X' && boardTwo.boardCells[6] == 'X' && boardThree.boardCells[6] == 'X')
score++;
if (boardOne.boardCells[7] == 'X' && boardTwo.boardCells[7] == 'X' && boardThree.boardCells[7] == 'X')
score++;
if (boardOne.boardCells[8] == 'X' && boardTwo.boardCells[8] == 'X' && boardThree.boardCells[8] == 'X')
score++;
if (boardOne.boardCells[0] == 'X' && boardTwo.boardCells[1] == 'X' && boardThree.boardCells[2] == 'X')
score++;
if (boardOne.boardCells[2] == 'X' && boardTwo.boardCells[1] == 'X' && boardThree.boardCells[0] == 'X')
score++;
if (boardOne.boardCells[3] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[5] == 'X')
score++;
if (boardOne.boardCells[5] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[3] == 'X')
score++;
if (boardOne.boardCells[6] == 'X' && boardTwo.boardCells[7] == 'X' && boardThree.boardCells[8] == 'X')
score++;
if (boardOne.boardCells[8] == 'X' && boardTwo.boardCells[7] == 'X' && boardThree.boardCells[6] == 'X')
score++;
if (boardOne.boardCells[0] == 'X' && boardTwo.boardCells[3] == 'X' && boardThree.boardCells[6] == 'X')
score++;
if (boardOne.boardCells[6] == 'X' && boardTwo.boardCells[3] == 'X' && boardThree.boardCells[0] == 'X')
score++;
if (boardOne.boardCells[1] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[7] == 'X')
score++;
if (boardOne.boardCells[7] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[1] == 'X')
score++;
if (boardOne.boardCells[2] == 'X' && boardTwo.boardCells[5] == 'X' && boardThree.boardCells[8] == 'X')
score++;
if (boardOne.boardCells[8] == 'X' && boardTwo.boardCells[5] == 'X' && boardThree.boardCells[2] == 'X')
score++;
if (boardOne.boardCells[0] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[8] == 'X')
score++;
if (boardOne.boardCells[8] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[0] == 'X')
score++;
if (boardOne.boardCells[2] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[6] == 'X')
score++;
if (boardOne.boardCells[6] == 'X' && boardTwo.boardCells[4] == 'X' && boardThree.boardCells[2] == 'X')
score++;
}
public void CPUThreeDWinCheck(ThreeD boardOne, ThreeD boardTwo, ThreeD boardThree, ref int score) //new function to check CPU ThreeD wins
{
if (boardOne.boardCells[0] == 'O' && boardTwo.boardCells[0] == 'O' && boardThree.boardCells[0] == 'O')
score++;
if (boardOne.boardCells[1] == 'O' && boardTwo.boardCells[1] == 'O' && boardThree.boardCells[1] == 'O')
score++;
if (boardOne.boardCells[2] == 'O' && boardTwo.boardCells[2] == 'O' && boardThree.boardCells[2] == 'O')
score++;
if (boardOne.boardCells[3] == 'O' && boardTwo.boardCells[3] == 'O' && boardThree.boardCells[3] == 'O')
score++;
if (boardOne.boardCells[4] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[4] == 'O')
score++;
if (boardOne.boardCells[5] == 'O' && boardTwo.boardCells[5] == 'O' && boardThree.boardCells[5] == 'O')
score++;
if (boardOne.boardCells[6] == 'O' && boardTwo.boardCells[6] == 'O' && boardThree.boardCells[6] == 'O')
score++;
if (boardOne.boardCells[7] == 'O' && boardTwo.boardCells[7] == 'O' && boardThree.boardCells[7] == 'O')
score++;
if (boardOne.boardCells[8] == 'O' && boardTwo.boardCells[8] == 'O' && boardThree.boardCells[8] == 'O')
score++;
if (boardOne.boardCells[0] == 'O' && boardTwo.boardCells[1] == 'O' && boardThree.boardCells[2] == 'O')
score++;
if (boardOne.boardCells[2] == 'O' && boardTwo.boardCells[1] == 'O' && boardThree.boardCells[0] == 'O')
score++;
if (boardOne.boardCells[3] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[5] == 'O')
score++;
if (boardOne.boardCells[5] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[3] == 'O')
score++;
if (boardOne.boardCells[6] == 'O' && boardTwo.boardCells[7] == 'O' && boardThree.boardCells[8] == 'O')
score++;
if (boardOne.boardCells[8] == 'O' && boardTwo.boardCells[7] == 'O' && boardThree.boardCells[6] == 'O')
score++;
if (boardOne.boardCells[0] == 'O' && boardTwo.boardCells[3] == 'O' && boardThree.boardCells[6] == 'O')
score++;
if (boardOne.boardCells[6] == 'O' && boardTwo.boardCells[3] == 'O' && boardThree.boardCells[0] == 'O')
score++;
if (boardOne.boardCells[1] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[7] == 'O')
score++;
if (boardOne.boardCells[7] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[1] == 'O')
score++;
if (boardOne.boardCells[2] == 'O' && boardTwo.boardCells[5] == 'O' && boardThree.boardCells[8] == 'O')
score++;
if (boardOne.boardCells[8] == 'O' && boardTwo.boardCells[5] == 'O' && boardThree.boardCells[2] == 'O')
score++;
if (boardOne.boardCells[0] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[8] == 'O')
score++;
if (boardOne.boardCells[8] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[0] == 'O')
score++;
if (boardOne.boardCells[2] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[6] == 'O')
score++;
if (boardOne.boardCells[6] == 'O' && boardTwo.boardCells[4] == 'O' && boardThree.boardCells[2] == 'O')
score++;
}
~ThreeD()
{
for (int c = 0; c < 10; c++)
{
boardCells[c] = '\0';
}
}
}
static void Main(string[] args)
{
ThreeD boardOne; //1st of three objects for first board
ThreeD boardTwo; //2nd
ThreeD boardThree; //3rd
int boardSelection = 0; //picks witch object to mark in
int counter = 0; //counter for while loop
int playerOneScore = 0; //score for user
int CPUScore = 0; //score for cpu
int CPUBoardSelection = 0;
Random rand = new Random();
int randomNum = rand.Next(1, 2);
if (randomNum == 1) // if randomNum = 1, user goes first
{
Console.WriteLine("You first");
while (true)
{
boardOne.getBoardCells();
boardTwo.getBoardCells();
boardThree.getBoardCells();
Console.WriteLine("Choose which board you wish to mark in. (1 - 3)"); //promts you to pick board
bool board = false;
المحلول 3
نصائح أخرى
Yes, the compiler is right: you're trying to use unassigned variables:
static void Main(string[] args)
{
// It's just a declaration; no value assigned to boardOne; boardOne contains trash
ThreeD boardOne;
// It's just a declaration; no value assigned to boardTwo; boardTwo contains trash
ThreeD boardTwo;
// It's just a declaration; no value assigned to boardThree; boardThree contains trash
ThreeD boardThree;
....
if (randomNum == 1)
{
Console.WriteLine("You first");
while (true)
{
boardOne.getBoardCells(); // <- And here you're trying to access the trash
It should be something like that:
static void Main(string[] args)
{
// boardOne is declared and assigned
ThreeD boardOne = new ThreeD();
// boardTwo is declared and assigned
ThreeD boardTwo = new ThreeD();
// boardThree is declared and assigned
ThreeD boardThree = new ThreeD();
....
if (randomNum == 1)
{
Console.WriteLine("You first");
while (true)
{
boardOne.getBoardCells(); // <- Quite OK
Firstly, boardOne, boardTwo and boardThree are variables, in this case are local variables scoped to the Main() method. Like any other variable, they need a valid data type, in your case the type is the ThreeD class. But this alone don't makes them objects, only defines their data type.
The variables only become objects when you use this class to create a new instance (a new single object in memory). So they must be initialized:
ThreeD boardOne = new ThreeD();
ThreeD boardTwo = new ThreeD();
ThreeD boardThree = new ThreeD();
This way, when the method getBoardCells() is called, each variable points to the object in memory they represent, which contains that method. Without the assignment, the variables are equal null by default. And of course, as null haven't a method getBoardCells() the compiler error you got makes all sense.
In order to use a local variable, you have to initialize it:
var boardOne = new ThreeD();
var boardTwo = new ThreeD();
...
You have to initialize your board objects becuase C# compiler does not allow the use of uninitialized variables. Check this link : Compiler Error CS0165
static void Main(string[] args)
{
ThreeD boardOne = new ThreeD(); //1st of three objects for first board
ThreeD boardTwo = new ThreeD(); //2nd
ThreeD boardThree = new ThreeD();
//..............
// ..............
}
your missing creating object instance
ThreeD boardOne = new ThreeD();
ThreeD boardTwo = new ThreeD();
ThreeD boardThree = new ThreeD();
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