Compilare: user.cpp: In function ‘void solve()’: user.cpp:21:32: warning: passing NULL to non-pointer argument 3 of ‘void* memset(void*, int, size_t)’ [-Wconversion-null] memset(st, sizeof(st), NULL); ^ In file included from /usr/include/string.h:642:0, from /usr/include/c++/4.8/cstring:42, from user.cpp:3: In function ‘void* memset(void*, int, size_t)’, inlined from ‘void solve()’ at user.cpp:21:33: /usr/include/i386-linux-gnu/bits/string3.h:82:32: warning: call to ‘__warn_memset_zero_len’ declared with attribute warning: memset used with constant zero length parameter; this could be due to transposed parameters [enabled by default] __warn_memset_zero_len (); ^ /tmp/cc7bcIkw.o: In function `solve()': user.cpp:(.text+0x5): warning: memset used with constant zero length parameter; this could be due to transposed parameters