Compilare: user.cpp: In function ‘int main()’: user.cpp:30:17: warning: unused variable ‘sum’ [-Wunused-variable] int N,u,l,i,sum = 0, head = 1,tail =0,sum_max = 0; ^ user.cpp:31:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum2.in","r",stdin); ^ user.cpp:32:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sum2.out","w",stdout); ^ user.cpp:37:37: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer,dimensiune,1,stdin); ^