使用分离的功能打印动态二维矩阵

Question

I can't understand what's happening. I created a matrix following this post: Function to dynamically allocate matrix

To print the matrix, I created this function:

void PrintMatrix(uint8_t *matrix, size_t nrows, size_t ncols)
{

    // Prints matrix

    size_t i, j;

    printf("\n");

    for (i = 0; i < nrows; ++i) 
    {
            for (j = 0; j < ncols ; ++j) 
            {
            printf("%" PRIu8 "\t", matrix[i][j]);
            }

    printf("\n");
    }

    printf("\n");
}

This function results in a compilation error:

error: subscripted value is neither array nor pointer nor vector
      printf("%" PRIu8 "\t", matrix[i][j]);

In order to check the function, I copied the code inside main() and ran it, suprisingly without any problem, so, why it doesn't work when run as a separated function?

Answer 1

matrix is of type uint8_t * . It should be of type uint8_t (*)[ncols] if you are passing the array to the function call (which will convert to pointer to array).

Change

void PrintMatrix(uint8_t *matrix, size_t nrows, size_t ncols)

to

void PrintMatrix(size_t nrows, size_t ncols, unit8_t (*matrix)[ncols])