Compilare: user.cpp: In function ‘int main()’: user.cpp:48:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < r.size(); ++i) ^ user.cpp: In function ‘void read()’: user.cpp:16:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%s%s", a, b); ^