Compilare: user.cpp: In function ‘int main()’: user.cpp:6:9: warning: unused variable ‘i’ [-Wunused-variable] int n,k,i,nr; ^ user.cpp:4:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("subset2.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("subset2.out","w",stdout); ^ user.cpp:7:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^