Compilare: user.cpp: In function ‘void query(char*, int)’: user.cpp:76:21: warning: argument to ‘sizeof’ in ‘void* memset(void*, int, size_t)’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess] memset(sol,0,sizeof(sol)); ^ user.cpp:106:10: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] sol[k+1]=NULL; ^ user.cpp: In function ‘int main()’: user.cpp:118:19: warning: argument to ‘sizeof’ in ‘void* memset(void*, int, size_t)’ call is the same expression as the destination; did you mean to provide an explicit length? [-Wsizeof-pointer-memaccess] memset(c,0,sizeof(c)); ^