Compilare: user.cpp: In function ‘int main()’: user.cpp:17:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i <= strlen(a + 1); i += 8) ^ user.cpp:32:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < SOL.size(); ++ i) ^ user.cpp:36:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 8; i <= strlen(a + 1); i += 8) ^ /tmp/ccZ8T0gC.o: In function `main': user.cpp:(.text.startup+0x53): warning: the `gets' function is dangerous and should not be used.