Compilare: user.cpp: In function ‘int main()’: user.cpp:36:15: warning: unused variable ‘l2’ [-Wunused-variable] int l1,c1,l2,c2; ^ user.cpp:38:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zone.in","r",stdin); ^ user.cpp:39:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zone.out","w",stdout); ^ user.cpp:41:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:45:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld",&sum[i]); ^ user.cpp:52:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&m[i][j]); ^