View Compilation Error

0_0_6365201_19210.cpp: In function `int main()':
0_0_6365201_19210.cpp:30: error: no match for 'operator=' in 'p = 0'
0_0_6365201_19210.cpp:5: note: candidates are: BT& BT::operator=(const BT&)
0_0_6365201_19210.cpp:36: error: cannot convert `BT' to `BT*' for argument `1' to `BT* ct(BT*, int)'
0_0_6365201_19210.cpp:39: error: cannot convert `BT' to `BT*' for argument `1' to `void tr(BT*)'
0_0_6365201_19210.cpp:40: error: `pust' undeclared (first use this function)
0_0_6365201_19210.cpp:40: error: (Each undeclared identifier is reported only once for each function it appears in.)