summaryrefslogtreecommitdiff
path: root/reference/C/CONTRIB/SNIP/dblround.c
blob: 5870fdaa524714b35983cf7c15d7bfdf05001ada (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
/*
**  DBLROUND.C - Rounds a double to the nearest whole number
**  public domain by Ross Cottrell
*/

#include <float.h>
#include <limits.h>
#include <assert.h>

double round(double x)
{
      assert(1 == FLT_ROUNDS);
      x += 1.0 / DBL_EPSILON;
      return x - 1.0 / DBL_EPSILON;
}

#ifdef TEST

#include <stdio.h>
#include <stdlib.h>

void main(int argc, char *argv[])
{
      double val;
      char *dummy;

      while (--argc)
      {
            val = strtod((const char *)(*(++argv)), &dummy);
            printf("round(%g) = ", val);
            printf("%.12g\n", round(val));
      }
}

#endif /* TEST */