Compilare: user.cpp: In function ‘int main()’: user.cpp:6:9: warning: variable ‘a’ set but not used [-Wunused-but-set-variable] int n,i,a,b,c,d,e,x; ^ user.cpp:4:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {freopen ("12perm.in","r",stdin); ^ user.cpp:5:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("12perm.out","w",stdout); ^ user.cpp:7:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^