View Compilation Error

0_0_2869937_9487.cpp:9: error: field `A' has incomplete type
0_0_2869937_9487.cpp:55: error: expected `}' at end of input
0_0_2869937_9487.cpp: In member function `int NODE::main()':
0_0_2869937_9487.cpp:21: error: `A' undeclared (first use this function)
0_0_2869937_9487.cpp:21: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2869937_9487.cpp: At global scope:
0_0_2869937_9487.cpp:55: error: expected unqualified-id at end of input
0_0_2869937_9487.cpp:55: error: expected `,' or `;' at end of input