Error in double pointer to array parameter

Question

int main (void)
{
    int** arr = new int*[4];
    for (int i = 0; i < 4; i++) arr[i] = new int[4] {1, 0, 0, 1};

    const int* p = &(arr[0][0]);

    TFigure* test = new TFigure(arr, 4, 4);
    test->resolve();

    for (int i = 0; i < 4; i++) delete[] arr[i];
    delete[] arr;

    return 0;
}

where constructor declaration is line 57:

TFigure(int **ia, int n, int m)
    N = n;
    M =m;

    landscape = new int*[n];
    puddles = new int*[n];
    for (int i = 0; i < n; i++){
        landscape[i] = new int[m];
        puddles[i] = new int[n];
        for (int j = 0; j < m; j++)
            landscape[i][j] = *ia[i][j];
        }


    for (int i = 0; i < n; i++)
        for (int j = 0; j < 0; j++)
            if (i == 0 || i == N || j == 0 || j == M)
                puddles[i][j] = 0;
            else
                puddles[i][j] = 1;

    for (int i = 0; i < N; i++){
    for (int j = 0; j < M; j++)
    std::cout << puddles[i][j] << ' ';
    std::cout << std::endl;
    }
    for (int i = 0; i < N; i++){
    for (int j = 0; j < M; j++)
    std::cout << landscape[i][j] << ' ';
    std::cout << std::endl;
    }


};

but I have an error

57:43: error: invalid type argument of unary «*» (have «int»)

I don't understand what causes this.

Your code should work. Please show the whole definition of TFigure — Andy Prowl
– Andy Prowl, Commented Mar 9, 2013 at 12:03
agree with Andy Prowl above. btw, don't forget to delete test; as well. — varnie
– varnie, Commented Mar 9, 2013 at 12:08
What is that int* p used for? That variable doesn't make sense given that arr is a ragged (or jagged) array. Why is that declaration even there? You aren't using p in the code shown. And finally, what is line 57? — David Hammen
– David Hammen, Commented Mar 9, 2013 at 12:10

Joseph Mansfield · Accepted Answer · 2013-03-09 12:13:42Z

2

The problem is with this line:

landscape[i][j] = *ia[i][j];

ia[i][j] gives you an int which you then try to dereference. It seems like you really just want:

landscape[i][j] = ia[i][j];

I'm not sure if this was a mistake when copy and pasting or not, but your constructor definition is missing an opening {.

TFigure(int **ia, int n, int m) {
//                         Here ^

answered Mar 9, 2013 at 12:13

Joseph Mansfield

111k22 gold badges249 silver badges329 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Error in double pointer to array parameter

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related