Compilare: user.cpp: In function ‘int main()’: user.cpp:54:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1 ; i <= n && found < m ; ++ i) { ^ In file included from /usr/include/c++/4.8/cassert:43:0, from user.cpp:4: user.cpp:64:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] assert(found == m); ^ user.cpp:72:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i == n - m) ^