title: How can I access the elements of this matrix
body: <p>I found this question on code signal I have this struct how can I access the elements of this matrix</p>
  <p>Arrays are already defined with this interface:</p>
  <pre><code>typedef struct arr_##name {
      int size;
      type *arr;
  } arr_##name;
  
  arr_##name alloc_arr_##name(int len) {
      arr_##name a = {len, len &gt; 0 ? malloc(sizeof(type) * len) : NULL};
      return a;
  }
  
  int solution(arr_arr_integer matrix) 
  {}
  </code></pre>