int** array = new int*[sizeX];
for(int i = 0; i < sizeX; ++i)
    array[i] = new int[sizeY];

int array[sizeX];

 
int** readFile(FILE* fp, int* dim) {
    int i,j;
    int **matrix; // matrix pointer

    // read dimension of matrix
    fscanf(fp, "%d", dim);

    // allocate memory for first level pointer
    matrix = malloc(*dim * sizeof(int*));
    if(matrix == NULL) {
        printf("OOM while allocating row memory\n");
        exit(1);
    }
    
    // fill matrix row by row
    for(i = 0; i < *dim; i++) {
        // allocate memory for each row
        matrix[i] = malloc(*dim * sizeof(int));
        if(matrix[i] == NULL) {
            printf("OOM while allocating column memory\n");
            exit(1);
        }
        // read data from file
        for(j = 0; j < *dim; j++) {
            fscanf(fp, "%d", &matrix[i][j]);
        }
    }

    return matrix;
}