What does the following code produce?
<p>I don't know if this is a trick question or what, but when I try to run this piece of code, I get a few errors.  Do you think the teacher forgot to put in an #include line?</p>

<pre><code>#include &lt;iostream&gt;
#include &lt;vector&gt;
using namespace std;

int display(int val) {
    cout &lt;&lt; val &lt;&lt; ",";
}

int main() {
    int a[] = {1, -4, 5, -100, 15, 0, 5};
    vector&lt;int&gt; v(a, a + 7);

    sort(v.begin(), v.end(), greater&lt;int&gt;());
    for_each(v.begin(), v.end(), display);
}
</code></pre>

<p>.</p>

<pre><code>g++ -ggdb  -c test.cpp
test.cpp: In function 'int main()':
test.cpp:13:41: error: 'sort' was not declared in this scope
test.cpp:14:38: error: 'for_each' was not declared in this scope
make: *** [test.o] Error 1
</code></pre>

<p>Thanks</p>
