input.c

快速傅里叶分析的C算法程序

#include "stdio.h"
#include "conio.h"
#include "math.h"

#define PI 3.1415926

void main( void )
{
    int n;
    double x[256];

    FILE *fp;
    if((fp=fopen("input.txt","w"))==NULL) {
        printf("Can't open file!");
        getch();
        exit(0);
    }

    for( n = 0; n<256; n++ ) {

        x[n]  = 10.0 * sin( 2.0 * PI * n / 32.0 );
        x[n] +=  5.0 * sin( 2.0 * PI * n / 16.0 );
        x[n] += 20.0 * sin( 2.0 * PI * n / 4.0 - PI/2 );
        x[n] += 20.0 * sin( 2.0 * PI * n / 3.0 );
    }

    for( n = 0; n <256; n++ )
        fprintf( fp, " sample_x[%d] = %f; \n", n, x[n] );

}