Casting float to int seems to cause a change in value

Asked Dec 22 '15 at 00:59

Active Dec 22 '15 at 01:05

Viewed 31 times

Say I have the number 3.3, and I want to get just the decimal part. What I did was (I'm separating the code out to do one thing per line as much as possible):

float _x = 3.3;
float _j = _x - floor(_x);
printf("1. %f\n", _j);
_j *= 10;
printf("2. %f\n", _j);
int z = (int) _j;
printf("3. %d\n", z);

I'm getting the following output:

1. 0.300000
2. 3.000000
3. 2

What's happening in the casting of _j to int that causes the number to equal 2 instead?

asked Dec 22 '15 at 00:59

galois

http://stackoverflow.com/tags/floating-point/info – Michael Burr Dec 22 '15 at 01:05
1

Show a little more precision using something like `%16.16f` in your `printf()` call. – Michael Burr Dec 22 '15 at 01:08
1

Casting to `int` will truncate (which e.g. converts 2.999999 to 2), use the `round` function instead. – user3386109 Dec 22 '15 at 01:34

Casting float to int seems to cause a change in value

0 Answers0