Compilare: user.cpp: In function ‘int main()’: user.cpp:42:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();i++) ^ /tmp/ccbnKsbZ.o: In function `main': user.cpp:(.text.startup+0x4e): warning: the `gets' function is dangerous and should not be used.