Tic Tac Toe
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Write the game of Tic Tac Toe. It's a game with a 3 by 3 grid played by 2 players. One player places O markers and the other player places X markers. Each player takes turns placing his/her marker in order to get 3 of their markers to line up on the board. A player wins when 3 or their markers line up either horizontally, vertically or diagonally. If no player has their markers line up in that fashion, and the board is full, then the game is called a "Cat Game". Your program should output the winner of the game or "Cat Game" if there was no winner. The user should be prompted if they would like to play again when the game is over. If they choose to play again, the player who started second last game should go first. 

Hint:

We've only learned about linear arrays like this:

But we need a way to have a board that looks like this:

We can make our linear array act like a 2D grid by having a set index pattern as shown above where index 0 of our array would be the top left element on the board, element 1 would be the top middle element and so on. So the numbers in the 2D grid are the indecies of our array. This will act like a 2D grid even though we only have an array.