错误：&#39;operator *&#39;不匹配（操作数类型是&#39;std :: vector <std::complex<double> &gt;&#39;和&#39;std :: complex <double> “）

Question

I use the vector class with complex numbers and I have to multiply a vector of complex numbers with a complex number, like this:

vector< complex<double> > vec;
complex<double> z;
// some initialization of vec and z ...
vector< complex<double> > res;
res = vec*z;   // here is the error

error: no match for 'operator*' (operand types are 'std::vector<std::complex<double> >' and 'std::complex<double>')

Is it possible to overload operator* with these parameters?

Answer 1

Yes, this is possible. Here is how you can implement your own operator * for complex<T> :

template <typename T>
vector<complex<T>> operator *(const vector<complex<T>>& v, const complex<T> z) {
    vector<complex<T>> res;
    transform(v.begin(), v.end(), back_inserter(res), 
        [&](complex<T> x) -> complex<T> {
            return x * z;
        });
    return res;
}