Array Segmentation Fault char vs int

[MistahMoose]

Hi All, Little bit of a weird thing happening here, Curious why this works:

    char GameBoard[ROWS][COLM];
    
    for (int i =0; i <= ROWS; i++)
    {
        for(int j = 0; j <= COLM; j++)
        {
            GameBoard[i][j] = 'o'; 
        }
    }

and this gives a segmentation fault :

    int GameBoard[ROWS][COLM];
    
    for (int i =0; i <= ROWS; i++)
    {
        for(int j = 0; j <= COLM; j++)
        {
            GameBoard[i][j] = 1; 
        }
    }

I am totally stumped. They both should work, should they not?

[Cakana]

Your code has undefined behavior by default, and the symptom of it can be revealed differently in different situations.

The code should be :

for (int i =0; i < ROWS; i++)
    {
        for(int j = 0; j < COLM; j++)
        {
            GameBoard[i][j] = 1; 
        }
    }

Note that array subscript starts at 0, and finish at size - 1.

[MistahMoose]

Okay, I understand that it should have been < instead of <= (Was trying to get it to print the amount I desired.)

I think I just had a bit of a brain shortage.

I had forgotten that defining an array of size 3 means you get an array of positions
0,1,2
(I had set size to 2, thinking that I would get an array of 0,1,2)

So following that trend I setup my for loops incorrectly and ended up with seg faults.

Silly how the simple things elude you when you haven't programmed in awhile!

Thank you.

(Though still curious how a char array of size 2 can fill position 3 without seg fault)

[Cakana]

(Though still curious how a char array of size 2 can fill position 3 without seg fault)

You know what is right or wrong. Do not try to commit undefined behavior.

[kevinros]

I think that you need to share you output expected to have more idea or the full code.
thanks.