View Compilation Error

152066_0_2039.cpp
152066_0_2039.cpp(5) : error C2065: 'NULL' : undeclared identifier
152066_0_2039.cpp(5) : error C2446: '==' : no conversion from 'int' to 'double *'
        Conversion from integral type to pointer type requires reinterpret_cast, C-style cast or function-style cast
152066_0_2039.cpp(5) : error C2040: '==' : 'double *' differs in levels of indirection from 'int'
152066_0_2039.cpp(6) : error C2065: 'exit' : undeclared identifier
152066_0_2039.cpp(7) : warning C4508: 'main' : function should return a value; 'void' return type assumed