View Compilation Error

0_0_12033141_30232.cpp:14: error: declaration of `operator==' as non-function
0_0_12033141_30232.cpp:14: error: `gaptree' was not declared in this scope
0_0_12033141_30232.cpp:14: error: expected `,' or `;' before "const"
0_0_12033141_30232.cpp:19: error: expected declaration before '}' token