Compilare: user.cpp: In function ‘void perm(long int)’: user.cpp:9:9: warning: unused variable ‘j’ [-Wunused-variable] {long i,j; ^ user.cpp: In function ‘int main()’: user.cpp:23:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("permutari.in","r",stdin); ^ user.cpp:24:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("permutari.out","w",stdout); ^ user.cpp:25:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld",&n); ^