Compilare: main.cpp: In function 'void pwr(const Perm&, Perm&, const long long int&)': main.cpp:106:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < vcolor[i].size(); j++) ~~^~~~~~~~~~~~~~~~~~ main.cpp: In function 'void read_buffer()': main.cpp:17:50: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buffer, sizeof(char), BUFFER_SIZE, fin); ^