Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:16:9: warning: unused variable 'i' [-Wunused-variable] int i; ^ main.cpp: In constructor 'instream::instream(const char*)': main.cpp:39:44: 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); ^ main.cpp: In member function 'void instream::advance()': main.cpp:65:48: 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); ^