Compilare: user.cpp: In function ‘void dijkstra(int)’: user.cpp:54:15: warning: unused variable ‘pos’ [-Wunused-variable] int u, v, pos, cost, w; ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:110:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:137:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^