How to use complex number “i” in C++

Question

I am coding a simple DFT algorithm now and I want to use the complex number i in complex exponential. I saw somebody use #include and #include&

Answer 1

You can find details here

A simple approach would be

#include 

using std::complex;
const double pi = 3.1415;
void foo()
{
    complex val(polar(1, pi/2.0); Create a complex from its olar representation
}