Files
2025-09-12 18:55:25 +09:00

38 lines
751 B
C

/* Driver for routine bessi0 */
#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 val,x;
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 Function I0",27)) {
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 %12s %13s \n","x","actual","bessi0(x)");
for (i=1;i<=nval;i++) {
fscanf(fp,"%f %f",&x,&val);
printf("%6.2f %12.7f %12.7f\n",x,val,bessi0(x));
}
fclose(fp);
return 0;
}
#undef NRANSI