xbessik.c

Numerical Recipes in C的源代码

/* Driver for routine bessik */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NRANSI
#include "nr.h"
#include "nrutil.h"

#define MAXSTR 80

int main(void)
{
	char txt[MAXSTR];
	int i,nval;
	float ri,rk,rip,rkp,x,xnu,xri,xrk,xrip,xrkp;
	FILE *fp;

	if ((fp = fopen("fncval.dat","r")) == NULL)
		nrerror("Data file fncval.dat not found\n");
	fgets(txt,MAXSTR,fp);
	while (strncmp(txt,"Modified Bessel Functions",25)) {
		fgets(txt,MAXSTR,fp);
		if (feof(fp)) nrerror("Data not found in fncval.dat\n");
	}
	fscanf(fp,"%d %*s",&nval);
	printf("\n%s\n",txt);
	printf("%5s %7s\n%14s %16s %17s %16s\n%14s %16s %17s %16s\n",
		"xnu","x","ri","rk","rip","rkp","xri","xrk","xrip","xrkp");
	for (i=1;i<=nval;i++) {
		fscanf(fp,"%f %f %f %f %f %f",&xnu,&x,&ri,&rk,&rip,&rkp);
		bessik(x,xnu,&xri,&xrk,&xrip,&xrkp);
		printf("%5.2f %5.2f\n\t%16.6e %16.6e %16.6e %16.6e\n",xnu,x,ri,rk,rip,rkp);
		printf("\t%16.6e %16.6e %16.6e %16.6e\n",xri,xrk,xrip,xrkp);
	}
	fclose(fp);
	return 0;
}
#undef NRANSI