Compilare: user.cpp: In function ‘int main()’: user.cpp:61:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (u = 0; u < dist[i].size(); ++u) { ^ user.cpp:63:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (v = 0; v < g[dist[i][u]].size(); ++v) { ^ user.cpp: In function ‘char nextch(FILE*)’: user.cpp:21:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, BUF_SIZE, 1, f); ^