c snippet

test.c

#include "fft.h"

#include <stdlib.h>
#include <stdio.h>
#include <complex.h>
#include <math.h>
#include <time.h>
#define pi 3.14159265358979323846

int main(int argc, char* argv[]) {
    int n=24;
    double index[n];
    double signal[n];
    double complex result[n];
    double modulous[n];
    double degree[n];
    double i; //second
    int j; //index
    double fs = 1200;//frequency of sampling
    double time;

    //time index generation
    for (i=0,j=0;j<(n);j++)
    {
        index[j]=i;
        signal[j]=2*sin(2*pi*50.0*i);
        i+= (1)/fs;
    }

    time0=clock();
    fft_slow(signal,result,n);
    printf("FFT takes %f ms\n\n",clock()-time0);

    for (j=0;j<(n);j++)
    {
        if (j==0)
        {
            modulous[j]=cabs(result[j])/n;         
        }
        else if (j==n/2+1)
        {
            modulous[j]=cabs(result[j])/n;  
        }
        else
        {
            modulous[j]=cabs(result[j])*2/n;
        }
        printf("freq:%f value:%f\n",j*50.0,modulous[j]);

    }
}