View Compilation Error

0_0_14625543_15837.cpp: In function 'int main()':
0_0_14625543_15837.cpp:14:14: error: invalid operands of types 'double' and 'int' to binary 'operator%'
             n%=18;
              ^
0_0_14625543_15837.cpp:14:14: error:   in evaluation of 'operator%=(double, int)'