Compilare: user.cpp: In function ‘int main()’: user.cpp:38:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[x]=NULL; ^ user.cpp:40:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] b[y]=NULL; ^ user.cpp:49:17: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[x]=NULL; ^ user.cpp:51:17: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] b[y]=NULL; ^ user.cpp:67:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[x]=NULL; ^ user.cpp:69:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] b[y]=NULL; ^ user.cpp:87:15: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[xs]=NULL; ^ user.cpp:89:15: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] b[ys]=NULL; ^ user.cpp:18:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lampa.in","r",stdin); ^ user.cpp:19:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lampa.out","w",stdout); ^ user.cpp:20:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n",&n,&m); ^ user.cpp:21:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s",s); ^