traverseda
/
cpython
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Implement round() slightly different, so that for negative ndigits no 

additional errors happen in the last step.  The trick is to avoid
division by 0.1**n -- multiply by 10.0**n instead.
This commit is contained in:
Guido van Rossum 1998-05-09 14:42:25 +00:00
parent ae94cf292b
commit 1e162d3753
1 changed files with 14 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
Python/bltinmodule.c
View File

@ -1488,14 +1488,22 @@ builtin_round(self, args)
if (!PyArg_ParseTuple(args, "d|i:round", &x, &ndigits))
return NULL;
f = 1.0;
for (i = ndigits; --i >= 0; )
i = abs(ndigits);
while (--i >= 0)
f = f*10.0;
for (i = ndigits; ++i <= 0; )
f = f*0.1;
if (x >= 0.0)
return PyFloat_FromDouble(floor(x*f + 0.5) / f);
if (ndigits < 0)
x /= f;
else
return PyFloat_FromDouble(ceil(x*f - 0.5) / f);
x *= f;
if (x >= 0.0)
x = floor(x + 0.5);
else
x = ceil(x - 0.5);
if (ndigits < 0)
x *= f;
else
x /= f;
return PyFloat_FromDouble(x);
}
static PyObject *