View Compilation Error

0_0_35535409_5078.cpp: In function 'int main()':
0_0_35535409_5078.cpp:10:22: error: 'sort' was not declared in this scope
         sort(a, a + 3);
                      ^
0_0_35535409_5078.cpp:10:22: note: suggested alternative:
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/algorithm:62:0,
                 from 0_0_35535409_5078.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algo.h:4705:5: note:   'std::sort'
     sort(_RandomAccessIterator __first, _RandomAccessIterator __last,
     ^