Compilare: main.cpp: In member function 'char InFile::read_ch()': main.cpp:20:34: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin ) ; ^ main.cpp: In function 'int main()': main.cpp:155:12: warning: iteration 17 invokes undefined behavior [-Waggressive-loop-optimizations] pow[i] = ( pow[i-1] * b ) % MOD ; ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:154:18: note: within this loop for (i = 1 ; i <= 18 ; i++ ) ~~^~~~~