Compilare: user.cpp: In function ‘int bit_count_mod2(int, int, int)’: user.cpp:32:38: warning: suggest parentheses around ‘+’ in operand of ‘&’ [-Wparentheses] return (power*((x_zeros*y_ones)&1+(x_ones*y_zeros)&1))&1; ^ user.cpp: In function ‘int main()’: user.cpp:52:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("xor.in","r",stdin); ^ user.cpp:53:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("xor.out","w",stdout); ^ user.cpp:55:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&t,&mod); ^ user.cpp:57:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&x1,&y1,&x2,&y2); ^