Return first digit of an integer

Question

How in Java do you return the first digit of an integer.?

i.e.

345

Returns an int of 3.

Answer 1

Updated: log10 solution:

A variation on the log10 solution with no division.:

public int getFirstDigit(int x) {
    double e = Math.log10(Math.abs((long) x));
    return Double.valueOf(Math.pow(10.0, e - Math.floor(e))).intValue());
}

What's it doing?

1. cast the int to long (to handle the MIN_VALUE issue)
2. get the absolute value
3. calculate the log10
4. calculate the floor of the log10
5. subtract the floor from the log10 (the difference will be the fraction)
6. raise ten to the difference, giving you the value of the first digit.

while loop solution:

To handle Integer.MIN_VALUE and keep Math.abs() and the cast to long out of the loop:

public static int getFirstDigit(int i) {
    i = Math.abs(i / (Math.abs((long)i) >= 10 ) ? 10 : 1);
    while (i >= 10 ) 
        i /= 10;
    return i;
}