#include <stdio.h>
#include <math.h>
#include <complex.h>

#ifndef M_PI_2
#define M_PI_2 (3.1415927/2)
#endif

int main()
{
   double complex z = 5 * cexp(M_PI_2 *I);
   printf("%f * e^(%f * i) = %f + %f * i\n", cabs(z), carg(z), creal(z), cimag(z));

   return 0;
}