Compilare: user.cpp: In function ‘int main()’: user.cpp:39:9: warning: unused variable ‘sum’ [-Wunused-variable] int sum=0; ^ user.cpp:19:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("div3.in","r",stdin); ^ user.cpp:20:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("div3.out","w",stdout); ^ user.cpp:22:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&n,&k); ^ user.cpp:26:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&a); ^