CS50(2021) Filter - Blur - c

Question

I couldn't figure out why the blur doesn't work when I check with check50. The image becomes blurry, but the RGB values are wrong. I'm not sure what I did wrong. If anyone knows, please do tell.
This is the picture of my
results in check50.
This is my code:
// Blur image
void blur(int height, int width, RGBTRIPLE image[height][width])
{
RGBTRIPLE copy[height][width];
// Copy image
for (int h = 0; h < height; h++)
{
for (int w = 0; w < width; w++)
{
copy[h][w] = image[h][w];
}
}
for (int h = 0; h < height; h++)
{
for (int w = 0; w < width; w++)
{
int row[] = { h - 1, h, h + 1 };
int col[] = { w - 1, w, w + 1 };
int R = 0;
int G = 0;
int B = 0;
int num = 0;
for (int x = 0; x < 3; x++)
{
// Check whether they are in frame
if (row[x] < 0 || row[x] >= height)
{
continue;
}
if (col[x] < 0 || col[x] >= width)
{
continue;
}
// Add up the value
R += copy[row[x]][col[x]].rgbtRed;
G += copy[row[x]][col[x]].rgbtGreen;
B += copy[row[x]][col[x]].rgbtBlue;
num++;
}
// Average
int blurRed = round(R / num);
int blurGreen = round(G / num);
int blurBlue = round(B / num);
// Update pixel
image[h][w].rgbtRed = blurRed;
image[h][w].rgbtGreen = blurGreen;
image[h][w].rgbtBlue = blurBlue;
}
}
return;
}