View Compilation Error

0_0_27659010_1909.cpp: In function 'int main()':
0_0_27659010_1909.cpp:26:20: error: 'sort' was not declared in this scope
   sort(num, num + k);
                    ^
0_0_27659010_1909.cpp:26:20: note: suggested alternative:
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/algorithm:62:0,
                 from 0_0_27659010_1909.cpp:4:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algo.h:4705:5: note:   'std::sort'
     sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
     ^