Well, it's not the most elegant tic-tac-toe I've seen, but it's a good try for an early game.

However, it's hard to tell what's happening. If you want others to easily understands what you're doing, you should provide comments. Especially for what the functions will do, what they'll return, etc.

You should structure your programming better: For example, doEdges(), do this:


void doEdges(char gameBoard[3][3], int magicBoard[3][3])
{
int edges[4] = { 1, 7, 9, 3 };
for each (int edge in edges)
{
int row, col;
getPosByNum(magicBoard, edge, row, col);
char edgec = gameBoard[row][col];
if (edgec != ' ')
{
gameBoard[row][col] = 'O';
break;
}
}
return;
}


In switch statements, don't use goto, use break;

Also, You should try and be more modular, IE, don't have functions modify the game board, have them return what move the AI should go to, and have the calling function modify the game board

Finally, I think it's beatable. If Human goes left center, AI goes center. Human goes Top center, AI will go to an edge (since Check corners will not find an 'X'). Then Human goes Top Left, he has a winning situation:



x|x|
-----
x|o|
-----
|o|