<div class="solution-view">
    <h3>Run id: 623</h3>
            <pre>Main.cc: In function 'bool cmp(book, book)':
Main.cc:11:13: error: no match for 'operator&lt;' (operand types are 'book' and 'book')
     return x constexpr bool std::operator&lt;(const std::pair&lt;_T1, _T2&gt;&amp;, const std::pair&lt;_T1, _T2&gt;&amp;)
     operator&lt;(const pair&lt;_T1, _T2&gt;&amp; __x, const pair&lt;_T1, _T2&gt;&amp; __y)
     ^
/usr/include/c++/4.8.2/bits/stl_pair.h:220:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::pair&lt;_T1, _T2&gt;'
     return x bool std::operator&lt;(const std::reverse_iterator&lt;_Iterator&gt;&amp;, const std::reverse_iterator&lt;_Iterator&gt;&amp;)
     operator&lt;(const reverse_iterator&lt;_Iterator&gt;&amp; __x,
     ^
/usr/include/c++/4.8.2/bits/stl_iterator.h:297:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::reverse_iterator&lt;_Iterator&gt;'
     return x bool std::operator&lt;(const std::reverse_iterator&lt;_Iterator&gt;&amp;, const std::reverse_iterator&lt;_IteratorR&gt;&amp;)
     operator&lt;(const reverse_iterator&lt;_IteratorL&gt;&amp; __x,
     ^
/usr/include/c++/4.8.2/bits/stl_iterator.h:347:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::reverse_iterator&lt;_Iterator&gt;'
     return x bool std::operator&lt;(const std::move_iterator&lt;_Iterator&gt;&amp;, const std::move_iterator&lt;_IteratorR&gt;&amp;)
     operator&lt;(const move_iterator&lt;_IteratorL&gt;&amp; __x,
     ^
/usr/include/c++/4.8.2/bits/stl_iterator.h:1055:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::move_iterator&lt;_Iterator&gt;'
     return x bool std::operator&lt;(const std::move_iterator&lt;_Iterator&gt;&amp;, const std::move_iterator&lt;_Iterator&gt;&amp;)
     operator&lt;(const move_iterator&lt;_Iterator&gt;&amp; __x,
     ^
/usr/include/c++/4.8.2/bits/stl_iterator.h:1061:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::move_iterator&lt;_Iterator&gt;'
     return x bool std::operator&lt;(const std::basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp;, const std::basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp;)
     operator&lt;(const basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp; __lhs,
     ^
/usr/include/c++/4.8.2/bits/basic_string.h:2569:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::basic_string&lt;_CharT, _Traits, _Alloc&gt;'
     return x bool std::operator&lt;(const std::basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp;, const _CharT*)
     operator&lt;(const basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp; __lhs,
     ^
/usr/include/c++/4.8.2/bits/basic_string.h:2581:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::basic_string&lt;_CharT, _Traits, _Alloc&gt;'
     return x bool std::operator&lt;(const _CharT*, const std::basic_string&lt;_CharT, _Traits, _Alloc&gt;&amp;)
     operator&lt;(const _CharT* __lhs,
     ^
/usr/include/c++/4.8.2/bits/basic_string.h:2593:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   mismatched types 'const _CharT*' and 'book'
     return x bool std::operator&lt;(const std::vector&lt;_Tp, _Alloc&gt;&amp;, const std::vector&lt;_Tp, _Alloc&gt;&amp;)
     operator&lt;(const vector&lt;_Tp, _Alloc&gt;&amp; __x, const vector&lt;_Tp, _Alloc&gt;&amp; __y)
     ^
/usr/include/c++/4.8.2/bits/stl_vector.h:1421:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::vector&lt;_Tp, _Alloc&gt;'
     return x bool std::operator&lt;(const std::array&lt;_Tp, _Nm&gt;&amp;, const std::array&lt;_Tp, _Nm&gt;&amp;)
     operator&lt;(const array&lt;_Tp, _Nm&gt;&amp; __a, const array&lt;_Tp, _Nm&gt;&amp; __b)
     ^
/usr/include/c++/4.8.2/array:238:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::array&lt;_Tp, _Nm&gt;'
     return x constexpr bool std::operator&lt;(const std::tuple&lt;_Elements ...&gt;&amp;, const std::tuple&lt;_Elements ...&gt;&amp;)
     operator&lt;(const tuple&lt;_TElements...&gt;&amp; __t,
     ^
/usr/include/c++/4.8.2/tuple:824:5: note:   template argument deduction/substitution failed:
Main.cc:11:14: note:   'book' is not derived from 'const std::tuple&lt;_Elements ...&gt;'
     return x&lt;y;
              ^
Main.cc:12:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
</pre>
    </div>