Compilare: user.cpp: In function ‘int main()’: user.cpp:18:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < strlen(c) - 1; ++ i) ^ user.cpp:24:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (!ok && i + l < strlen(c)) ^ user.cpp:36:62: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i + l == strlen(c) - 1) ^ user.cpp:47:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (i + l == strlen(c) && !i) ^