Compilare: user.cpp: In function ‘int main()’: user.cpp:29:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j; ^ user.cpp:30:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abc.in","r",stdin); ^ user.cpp:31:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abc.out","w",stdout); ^ user.cpp:32:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&n,&b,&c); ^ user.cpp:34:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^