Compilare: user.cpp: In function ‘int main()’: user.cpp:62:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ctc.size(); ++i) { ^ user.cpp:64:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < ctc[i].size(); ++j) { ^ user.cpp:50:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d%d", &n, &m); ^ user.cpp:52:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d%d", &u, &v); ^