Files
2025-02-Numerical/lib/nr/ansi/examples/xhunt.c
2025-09-12 18:55:25 +09:00

46 lines
949 B
C

/* Driver for routine hunt */
#include <stdio.h>
#include <math.h>
#define NRANSI
#include "nr.h"
#include "nrutil.h"
#define N 100
int main(void)
{
unsigned long i,j,ji;
float x,*xx;
xx=vector(1,N);
/* create array to be searched */
for (i=1;i<=N;i++)
xx[i]=exp(i/20.0)-74.0;
printf("\n result of: j=0 indicates x too small\n");
printf("%14s j=100 indicates x too large"," ");
printf("\n%12s %8s %4s %11s %13s \n",
"locate:","guess","j","xx(j)","xx(j+1)");
/* do test */
for (i=1;i<=19;i++) {
x = -100.0+10.0*i;
/* trial parameter */
j=(ji=5*i);
/* begin search */
hunt(xx,N,x,&j);
if ((j < N) && (j > 0))
printf("%12.5f %6lu %6lu %12.6f %12.6f \n",
x,ji,j,xx[j],xx[j+1]);
else if (j == N)
printf("%12.5f %6lu %6lu %12.6f %s \n",
x,ji,j,xx[j]," upper lim");
else
printf("%12.5f %6lu %6lu %s %12.6f \n",
x,ji,j," lower lim",xx[j+1]);
}
free_vector(xx,1,N);
return 0;
}
#undef NRANSI