Compilare: user.cpp: In function ‘int main()’: user.cpp:67:28: warning: unused variable ‘M’ [-Wunused-variable] int l=2*v[1],h=2*v[N],m=0,M; ^ user.cpp:59:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sume2.in","r",stdin); ^ user.cpp:60:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sume2.out","w",stdout); ^ user.cpp:61:22: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(f,1,MAX,stdin); ^