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rnd_div.c
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rnd_div.c
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/*
** RND_DIV.C - Rounded integer division
**
** Public domain - suggested by Dave Hansen in comp.lang.c
*/
#include <stdlib.h>
int round_div(int n, int d)
{
div_t res = div(n,d);
div_t rnd = div(res.rem, (abs(d)+1)/2 );
return res.quot + rnd.quot;
}
long round_ldiv(long n, long d)
{
ldiv_t res = ldiv(n,d);
ldiv_t rnd = ldiv(res.rem, (abs(d)+1)/2 );
return res.quot + rnd.quot;
}
#ifdef TEST
#include <stdio.h>
#include <limits.h>
main(int argc, char *argv[])
{
long n, d, q;
if (argc != 3)
{
puts("Usage: RND_DIV n d\n");
puts("Returns n/d rounded to nearest integer");
return -1;
}
n = atol(argv[1]);
d = atol(argv[2]);
if (n > INT_MAX || d > INT_MAX)
{
q = round_ldiv(n, d);
printf("round_ldiv(%ld, %ld) = %ld\n", n, d, q);
}
else
{
q = (long)round_div((int)n, (int)d);
printf("round_div(%ld, %ld) = %ld\n", n, d, q);
}
return 0;
}
#endif /* TEST */