Compilare: user.cpp: In function ‘int main()’: user.cpp:26:19: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if((y-i)&1==0) { ~^~~ user.cpp:5:95: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pitagora2.in","r",stdin),freopen("pitagora2.out","w",stdout),scanf("%d",&n),r=n*n; ^ user.cpp:5:95: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] user.cpp:5:95: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]