Compilare: user.cpp: In function ‘int main()’: user.cpp:6:11: warning: unused variable ‘l’ [-Wunused-variable] int n,l,c=1,i; ^ user.cpp:4:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("regine.in","r",stdin); ^ user.cpp:5:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("regine.out","w",stdout); ^ user.cpp:7:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^