View Compilation Error

0_0_31149383_4535.cpp: In function 'int main()':
0_0_31149383_4535.cpp:5:11: error: expected unqualified-id before numeric constant
 #define g 9.80
           ^
0_0_31149383_4535.cpp:9:12: note: in expansion of macro 'g'
     double g=9.8;
            ^