Compilare: main.cpp: In function 'int main()': main.cpp:63:57: warning: statement has no effect [-Wunused-value] s+=((right*(right+1))/2)%mod-((left*(left+1))/2)%mod; ^ main.cpp:13:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("leftmax.in","r",stdin); ^ main.cpp:14:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("leftmax.out","w",stdout); ^