Overwriting a row of a dynamic 2D array in C

[bloob]

Hello! I have been trying to come up with a code that overwrites a row of a dynamic 2D array/matrix for quite some time, and when I thought I managed to do it turns out it works for `number of rows>number of columns`type of a matrix only. I am fairly new to this and can not seem to find an error .

printf("Enter a number of a row you wish to delete: ");
            scanf_s("%d", &k);
            if (k >= 0 && k < vr) { //vr is number or rows
              for (i = 0; i < kol; i++) { //kol -nmbr of columns
                    unsigned int *tmp;
                    for (j = k + 1; j < vr; j++) a[j - 1][i] = a[j][i];
                    tmp = realloc(a[i], (vr - 1) * sizeof(unsigned int));
                    if (tmp == NULL) {
                        printf("ERROR\n");
                        exit(1);
                    }
                    else a[i] = tmp;
                }
                vr--;

[Salem]

How is a declared in the first place?

If you're starting with
unsigned int **a = malloc( nRows * sizeof(*a));

Where each row is
a[i] = malloc( nCols * sizeof(*a[i]));


To remove a row, it's simply
free(a[i]);
for (j = i+1; j < nRows ; j++) a[j-1] = a[j];


After that, you can use realloc to make a itself shorter, and decrement nRows.

> //vr is number or rows
So change the variable to be something actually readable, then you don't need meaningless comments.