D.cpp: In function 'int main()':
D.cpp:47:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
In file included from /usr/include/c++/4.6/algorithm:63:0,
from D.cpp:3:
/usr/include/c++/4.6/bits/stl_algo.h: In function '_RandomAccessIterator std::__unguarded_partition(_RandomAccessIterator, _RandomAccessIterator, const _Tp&, _Compare) [with _RandomAccessIterator = pt*, _Tp = pt, _Compare = bool (*)(pt&, pt&)]':
/usr/include/c++/4.6/bits/stl_algo.h:2265:78: instantiated from '_RandomAccessIterator std::__unguarded_partition_pivot(_RandomAccessIterator, _RandomAccessIterator, _Compare) [with _RandomAccessIterator = pt*, _Compare = bool (*)(pt&, pt&)]'
/usr/include/c++/4.6/bits/stl_algo.h:2306:62: instantiated from 'void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size, _Compare) [with _RandomAccessIterator = pt*, _Size = long int, _Compare = bool (*)(pt&, pt&)]'
/usr/include/c++/4.6/bits/stl_algo.h:5445:4: instantiated from 'void std::sort(_RAIter, _RAIter, _Compare) [with _RAIter = pt*, _Compare = bool (*)(pt&, pt&)]'
D.cpp:34:20: instantiated from here
/usr/include/c++/4.6/bits/stl_algo.h:2233:4: error: invalid initialization of reference of type 'pt&' from expression of type 'const pt'
/usr/include/c++/4.6/bits/stl_algo.h:2236:4: error: invalid initialization of reference of type 'pt&' from expression of type 'const pt'
D.cpp: In function 'int main()':
D.cpp:27:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
D.cpp:30:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]