View Compilation Error

0_0_33830328_21519.cpp: In member function 'bool bg::operator<(bg) const':
0_0_33830328_21519.cpp:12:27: error: 'a' was not declared in this scope
         if(t==B.t) return a.l<b.l;
                           ^
0_0_33830328_21519.cpp:12:31: error: 'b' was not declared in this scope
         if(t==B.t) return a.l<b.l;
                               ^