View Compilation Error

0_0_33159170_929.cpp: In function 'double length(Poi)':
0_0_33159170_929.cpp:22:34: error: invalid operands of types 'double(Poi, Poi)' and 'int' to binary 'operator%'
 db length(Poi a){return sqrt(dot%2
                                  ^
0_0_33159170_929.cpp:22:34: error: expected ';' at end of input
0_0_33159170_929.cpp:22:34: error: expected '}' at end of input