Compilare: user.cpp: In function ‘short int submatrix(int, int)’: user.cpp:114:31: warning: suggest parentheses around ‘+’ inside ‘<<’ [-Wparentheses] int ax = x-(x%(pw<<1))+pw<<1; ~~~~~~~~~~~~~^~~ user.cpp:115:31: warning: suggest parentheses around ‘+’ inside ‘<<’ [-Wparentheses] int ay = y-(y%(pw<<1))+pw<<1; ~~~~~~~~~~~~~^~~ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:16:38: 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); ^