Question

I have written a piece of code that uses complex library. I have put the definition of my function in a header file and in the main.cpp i have defined the complex number “I” as you can see in my codes below.
But when i want to compile this code i receive errors.

I think the function in the header file can not use complex library.
How can i fix this problem?

Thanks.

main.cpp

#include <iostream>
#include "math.h"
#include <complex>
#include "header.h"

using namespace std;
typedef complex<double> cmp;
cmp I(0.0,1.0);

int main()
{
cout << function(5.0) << endl;

return 0;
}

header.h

#ifndef header
#define header

double function(double x)
{
return 5*exp(I*x).real();
}

#endif

Answer 1

The problem is that I is not defined when your header file is parsed. You would need to move the definition of I before the #include "header.h".