Compilare: user.cpp: In function ‘int main()’: user.cpp:22:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (x%k==n) { ^ user.cpp:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ((x*10+2)%k==n) { ^ user.cpp:34:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ((x*10+3)%k==n) { ^ user.cpp:40:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ((x*10+5)%k==n) { ^ user.cpp:46:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if ((x*10+7)%k==n) { ^ user.cpp:11:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cifre4.in","r",stdin); ^ user.cpp:12:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cifre4.out","w",stdout); ^ user.cpp:13:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^ user.cpp:16:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^