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copied!<p>You usually go through the list until you reach the tail item while counting in the meanwhile, code should be something like that:</p> <pre><code>int listLength(struct Data_Struct* item) { struct Data_Struct* cur = item; int size = 0; while (cur != null) { ++size; cur = cur->Next; } return size; } </code></pre> <p>Mind that complexity of this operation is linear with the size of the list, so it's <em>O(n)</em> and it's quite inefficient. You could store size somewhere and update with list insertions and deletes to avoid any overhead and being able to calculate it in a constant time <em>O(1)</em>.</p> <p><strong>EDIT:</strong> Didn't notice you wanted size of the whole data included into the list. In your case you can keep the same approach used for calculating the length but instead that adding <strong>1</strong> for every element you should add the total length of strings:</p> <pre><code>size += strlen(Name)+strlen(Task)+strlen(Pos); </code></pre> <p>Mind that since data inside your list element if of type <code>char*</code> the effective size of the <code>Data_Struct</code> is just 4 pointers, that's why you need to use a support function like <code>strlen</code>, otherwise you can't get <em>real</em> dimension of the strings.</p> <p>Which is the difference?</p> <pre><code>sizeof(Data_Struct) == 16 </code></pre> <p>because the <code>Data_Struct</code> type contains 4 pointers, three for pointers to char and one for the next element in the list</p> <pre><code>sizeof(Name) == sizeof(Task) == sizeof(Pos) == 4 </code></pre> <p>because these variables are of type <em>pointer to char</em>, so they are pointer, no concrete value, and it's usually 4 bytes (I'm assuming a 32 bit architecture)</p> <pre><code>strlen(Name) == length in chars of the string </code></pre> <p>because the function works exactly to calculate the length of a string.</p>

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