View Compilation Error

0_0_24822390_27770.cpp: In function 'std::vector<long long int> convolution(const std::vector<long long int>&, ll)':
0_0_24822390_27770.cpp:82:28: error: invalid cast from type 'std::complex<double>' to type 'll {aka long long int}'
         b[i] = (ll)(x[i]+.5)%mod;
                            ^
0_0_24822390_27770.cpp: In function 'int main()':
0_0_24822390_27770.cpp:108:24: error: 'n' was not declared in this scope
     while(scanf("%d", &n), n){
                        ^