Tic Tac Toe AI issue in C - c

Question

I tried making a simple tic tac toe project, and I am trying to make the AI move to random places, so that the AI just moves into any available place. However, it always makes 2 moves. I am wondering why it always makes 2 moves instead of just 1.
What I mean is, let's say the user inputs 'O' into slot 1,1.
0 1 2
+----+----+----+
0 | | | |
| | | |
+----+----+----+
| | | |
1 | | O | |
+----+----+----+
| | | |
2 | | | |
+---------------
Then the computer moves 2 moves: into slots 1,2 AND 2,0
0 1 2
+----+----+----+
0 | | | |
| | | |
+----+----+----+
| | | |
1 | | O | X |
+----+----+----+
| | | |
2 | X | | |
+---------------
So I'd like to know why this happens?
Here is my code:
void compMove(char board[][columns])
{
int randomNum, randomNum1, i, j;
bool didMove = FALSE;
srand((int)time(NULL)); //Seed the random number generator
randomNum = rand() % 3;
randomNum1 = rand() % 3;
while(board[randomNum][randomNum1] != ' ')
{
randomNum = rand() % 3;
randomNum1 = rand() % 3;
}
for(i = 0; i < 3; i++)
{
for(j = 0; j < 3; j++)
{
if(i == randomNum && j == randomNum1)
{
board[i][j] = 'X';
didMove = TRUE;
break;
}
}
if(didMove == TRUE) break;
}
}

Answer 1

You do not need a loop to set movement on the board.
board[randomNum][randomNum1] = 'X';
is enough to set.
And you probably call this function twice, because function plays only one move.

Answer 2

I suspect your checkWin function is the culprit. Probably has an = somewhere you meant to have an ==. But that's just a guess without seeing it.
Your compMove function is grossly overcomplicated, but not wrong. Here's code that does the same thing:
void compMove(char board[][columns]) {
int row, col;
/* DON'T seed RNG here; do it once in main() */
do {
row = rand() % 3;
col = rand() % 3;
} while (board[row][col] != ' ');
board[row][col] = 'X';
}