Compilare: user.cpp: In function ‘bool pairup(int)’: user.cpp:19:9: warning: unused variable ‘y’ [-Wunused-variable] int y, i, l = ls[x].size(); ^ user.cpp:19:12: warning: unused variable ‘i’ [-Wunused-variable] int y, i, l = ls[x].size(); ^ user.cpp:19:15: warning: unused variable ‘l’ [-Wunused-variable] int y, i, l = ls[x].size(); ^ user.cpp: In function ‘int main()’: user.cpp:40:10: warning: unused variable ‘s’ [-Wunused-variable] char s[100]; ^ 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 ‘int main()’ at user.cpp:65:36: /usr/include/i386-linux-gnu/bits/string3.h:85:70: warning: call to void* __builtin___memset_chk(void*, int, unsigned int, unsigned int) will always overflow destination buffer [enabled by default] return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest)); ^