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copied!<p>There four problems with the implementation of your code:</p> <ol> <li>It doesn't copy the elements of the list.</li> <li>It doesn't assign the value of <code>new_list</code> to the <code>list</code> variable in <code>main</code></li> <li>It inserts values from the back to the front, instead of after the last value</li> <li><code>max_size</code> doesn't get updated. It's easy to miss this, because you only increase the size of the array by one each time. That way it would need to allocate each time a value is added. If you increase the new size by more then one it will still reallocate every time.</li> </ol> <p>The first problem can be fixed by changing the for loop in <code>list_add</code> so it makes a copy:</p> <pre><code>for (int i = 0; i < space_used; i++) { // this also changed. list_new[i] = list[i]; cout ... } // insert the new value (in the front?) list_new[max_size-space_used-1] = value; delete [] list; // Delete the list afterwards instead of earlier. </code></pre> <p>The second problem can by fixed by returning a pointer to the list. Change the <code>main</code> function to this:</p> <pre><code>for (int i = 0; i < 11; i++) { list = list_add(list, used, N, i); } </code></pre> <p>The third problem can be fixed by changing this line</p> <pre><code>list_new[max_size-space_used-1] = value; </code></pre> <p>to</p> <pre><code>list_new[space_used++] = value; </code></pre> <p>You should also remove the <code>space_used++</code> after this.</p> <p>To see the fourth problem you should change this line</p> <pre><code>int new_max_size = space_used+1; </code></pre> <p>to </p> <pre><code>int new_max_size = space_used+3; </code></pre> <p>It will still reallocate every time. It should however reallocate only two times.</p> <hr> <p>This is the full code:</p> <pre><code>#include <iostream> using std::cout; using std::endl; int* list_add(int *list, int& space_used, int& max_size, int value) { if (max_size - space_used > 0) { list[space_used++] = value; return list; } else { cout << "Increasing size of array!" << endl; int new_max_size = space_used+1; int *list_new = new int[new_max_size]; for (int i = 0; i < space_used; i++) { list_new[i] = list[i]; cout << list_new[i] << ". "; } cout << endl; list_new[space_used++] = value; max_size=new_max_size; delete [] list; return list_new; } } int main() { int N = 7; //declaring dynamic array allocation int* list = new int[N]; int used = 0, a_val; for (int i = 0; i < 11; i++) { list=list_add(list, used, N, i); } cout << endl << "Storlek: " << N << endl << endl; cout << "Printar listan " << endl; for (int i = 0; i < used; i++) { cout << list[i] << ". "; } } </code></pre>

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