Rounding without inline method

Question

I want to round a float variable to int without using an inline method. It will look like

13.4 => 13
13.49 => 13
13.5 => 14
13.6 => 14

So far this is the closest thing I could get to, but I'm not sure if it is effective.

int Roundoff(float num)
{
    int temp = (int) num;

    num *= 10;
    if(num%10 >= 5)
    {
        return temp + 1;
    }
    else
    {
        return temp;
    }

}

Answer 1

You can try the following:

int Roundoff(float num) {
  return num < 0 ? (int) (num - 0.5) : (int) (num + 0.5);
}

There is a trick with negative values ​​(you cannot just add 0.5):

  -13.9 -> -14.0
  -13.1 -> -13

And be careful, as

  int.MaxValue < float.MaxValue
  int.MinValue > float.MinValue

Answer 2

Well, you already use casting, and sometimes it can give you exactly what you need. If you just add 0.5 to your number and then produce an integer, you get a rounded value.

13.4 + 0.5 = 13.9 -> 13 (when casted to int)
13.49 + 0.5 = 13.99 -> 13
13.5 + 0.5 = 14.0 -> 14
13.6 + 0.5 = 14.1 -> 14

Here is how you could write a method.

int Roundoff(float num)
{
    return (int) (num + 0.5);
}

Answer 3

float f = 0.3;  // Or whatever
int i = (int) (f + 0.5f);