Thread: scanf/printf unexpected behavior

Ok, so over the summer I started making a simple tic-tac-toe program in my spare time to get some practice with pointers, structs, and programming in C in general. Overall, the program has been going great, no major issues. However, there is one area I am having a bit of confusion.

When I started this project, at the beginning of the summer, I had only a small understanding of C, with my first CS class being in C++. As such, I was not too familiar with how to read input from stdin, so I ended up using getchar(). Now, I am trying to change my input to use scanf() instead. At one point in particular, this is causing some small issues. Reference the code block below:

Code:

int main(int argc, char **argv)
{
        if (system("cls"))
                system("clear");

        printf("TicTacToe v1.0\nBy Daniel Bauer\n\n");

        printf("Number of games to play: ");

        int games, i;
        if(scanf("%d", &games) == 0)
        {
                printf("Input error, expected integer\n");
                return 0;
        }

        for(i = 0; i < games; i++)
        {
                if (system("cls"))
                        system("clear");
                board *gameBoard = initializeBoard( );
                while(gameBoard->human != 'X' && gameBoard->human != 'O')
                {
                        printf("Pick X or O: ");
                        scanf("%c", &gameBoard->human);
                        gameBoard->human = toupper(gameBoard->human);
                }

                if(gameBoard->human == 'X')
                        gameBoard->computer = 'O';
                else
                        gameBoard->computer = 'X';

                ...

This part of code is supposed to read in the number of games the user wants to play and then whether the player wants to be X or O. The problem is that when the program gets to asking the player X or O, it will print "Pick X or O: Pick X or O: ", when I would prefer it only print that once.

Does anyone here know what might be causing this? Any help with fixing my code or a workaround would be appreciated.

And if for whatever reason you need to see more of the code, just let me know!

Question 12.18a