View Compilation Error

0_0_33817570_23010.cpp: In function 'int main()':
0_0_33817570_23010.cpp:10:11: error: 'second' was not declared in this scope
 #define a second
           ^
0_0_33817570_23010.cpp:74:18: note: in expansion of macro 'a'
    t.a=b[c[i]].a;a
                  ^