Compilare: user.cpp:24:17: warning: character constant too long for its type [enabled by default] if(strchr(q,'qwertyuiopasdfghjklzxcvbnm')!=NULL) ^ user.cpp: In function ‘int main()’: user.cpp:21:11: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] q[m+1]=NULL; ^ user.cpp:38:16: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] z[lg-k]=NULL; ^ user.cpp:40:18: warning: NULL used in arithmetic [-Wpointer-arith] if(z[0]==NULL) ^