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copied!<p>I'd suggest that you make <code>ptr_friends</code> a pointer to multiple chars by using <code>malloc(size_t)</code> and then resizing the space with <code>realloc(void *, size_t)</code> everytime you want to add an ID to the friendlist. That way you can just get the numbers using <code>ptr_friends[i]</code>.</p> <p>For example :</p> <pre><code>int friends_size = 1; char *ptr_friends = malloc((size_t)1); ptr_friends[0] = john_id; // john_id is a fictional ID here </code></pre> <p>And when you want to add a friend :</p> <pre><code>ptr_friends = realloc(ptr_friends, ++friends_size); ptr_friends[friends_size-1] = mary_id; </code></pre> <p><strong>EDIT :</strong></p> <p>If you want to make a function to add a friend, for example <code>addfriend(char *,int)</code>, doing the following is an error :</p> <pre><code>void addfriend(char *ptr_friends, int *friends_size, int id) { ptr_friends = realloc(ptr_friends, (size_t) ++(*friends_size)); ptr_friends[friends_size-1] = id; } </code></pre> <p><code>ptr_friends</code> here is getting reallocated, and since the pointer can move while being reallocated, we're storing it in <code>ptr_friends</code>. But, it's the <code>ptr_friends</code> from <strong>inside</strong> the function, that means that the pointer we give to the function will <strong>not</strong> get modified, since arguments to a function are <strong>copied</strong> elsewhere beforehand. That means that you have to give a pointer to the pointer, so you can modify the pointer in the main code.</p>

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