/*時間抽選基4?16點FFT及IFFT算法C語言實現*/
#include?“stdio.h“
#include?“math.h“
#define?N?32

/*定義復數類型*/
typedef?struct{
?????double?real;
?????double?img;
}complex;

complex?x[N]?*W;?/*輸入序列旋轉因子*/
int?size_x=64;?????/*輸入序列的大小，在本程序中僅限4的次冪*/
double?PI;????????/*圓周率*/

int?main（）{
?????int?imethod;
?????void?fft（）;????/*快速傅里葉變換*/
?????void?ifft（）;
?????void?initW（）;??/*初始化變換核*/
?????void?change（）;?/*變址*/
?????void?add（complex?acomplex?bcomplex?*c）;?/*復數加法*/
?????void?mul（complex?acomplex?bcomplex?*c）;?/*復數乘法*/
?????void?sub（complex?acomplex?bcomplex?*c）;?/*復數減法*/

?????void?output（）;????????????????????????????/*輸出結果*/
?????system（“cls“）;
?????PI=atan（1）*4;
//?????printf（“Please?input?the?size?of?x:\n“）;
//?????scanf（“%d“&size_x）;
?????printf（“Please?input?the?data?in?x[N]:\n“）;
?????for（i=0;i???????????scanf（“%lf%lf“&x.real&x.img）;
//?????initW（）;
//?????printf（“Use?FFT（0）?or?IFFT（1）?\n“）;
//?????scanf（“%d“&method）;
//?????if（method==0）
//???????????fft（）;
//?????else
//???????????ifft（）;
//?????output（）;
//?????return?0;
}

void?add（complex?acomplex?bcomplex?*c）{
?????c->real=a.real+b.real;
?????c->img=a.img+b.img;
}

void?mul（complex?acomplex?bcomplex?*c）{
?????c->real=a.real*b.real?-?a.img*b.img;
?????c->img=a.real*b.img?+?a.img*b.real;
}
void?sub（complex?acomplex?bcomplex?*c）{
?????c->real=a.real-b.real;
?????c->img=a.img-b.img;
}

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????1510??2010-05-23?22:17??fft-16-4.c

-----------?---------??----------?-----??----

?????????????????1510????????????????????1