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

#include <stdint.h>

// Number of samples.
typedef enum TE_CONSTS
{
    N = 256,
} E_CONSTS;

// 
int n;

//
int k;

// sample array.
static int ReXn[N];
static int ImXn[N];

// frequency bins.
static double ReXf[N];
static double ImXf[N];

static double ReTmp;
static double ImTmp;


int main(int argc, char **argv)
{
    // step function at t=0 to t=7.
    ReXn[0]=1;
    ReXn[1]=1;
    ReXn[2]=1;
    ReXn[3]=1;
    ReXn[4]=1;
    ReXn[5]=1;
    ReXn[6]=1;
    ReXn[7]=1;
    
    for (k = 0; k < N; ++k)
    {
        ReTmp = 0.0;
        ImTmp = 0.0;
        
        for (n = 0; n < N; ++n)
        {
            ReTmp += ReXn[n] * cos((2*M_PI*n*k)/N) * 255;
            ImTmp += ReXn[n] * sin((2*M_PI*n*k)/N) * 255;
        }
        
        ReXf[k] = ReTmp;
        ImXf[k] = ImTmp;
        
        printf("X[%d]: %f + %fj\n", k, ReXf[k], ImXf[k]);
    }
    
    for (k = 0; k < N; ++k)
    {
        printf("%f\n", sqrt(ReXf[k]*ReXf[k] + ImXf[k]*ImXf[k]));
    }
    
    return 0;
}