Is there a way to write a method that outputs the number of digits before the decimal point of a float parameter as a short?

Question

I need to output the total number of digits before the decimal point of a float number and output the results as a short.

This is what I have so far:

public static void main(String[] args) {
    
    DigitsBeforeDot(18.879);

}

public static short DigitsBeforeDot(float x){
    
    short a = (short) x;
    
    System.out.println((short)Math.log10(a)+1);
    
    return a;
}

I get a suggestion to cast the argument in the method to a float like this:

public static void main(String[] args) {
    
    DigitsBeforeDot((float) 18.879);

}

And this makes the program work but I need to make it work without the casting by changing something in the method.

What is the best way to do that?

Answer 1

1. Stick to naming conventions. public static short DigitsBeforeDot(float x){ should be public static short digitsBeforeDot(float x) { or even better: public static short getDigitsBeforeDot(float x) { or public static short calculateDigitsBeforeDot(float x) {

2. Use a source code formatter if your IDE provides one

3. Instead of working with float and int , go with double and long . Apart from storing values in arrays (RAM consumption) there is no downside to using the full register width (64bit) of modern platforms. The upside is that you're a lot less likely to run into problems with precision or overflows.

4. It's highly unlikely that you want partial/float/fractions of the number of digits (like 2.176 as a result for log10(150) ). It's a lot more likely you want the integer number returned, ie 2 . So you should use an byte/short/int/long as return value. I recommend usnig long : public static long calculateDigitsBeforeDot(double x) { , and instead of casting the log10 to a short , you just cast it to a long instead. Java always rounds towards zero, so that would equal a call to Math.floor(Math.log10(a)) + 1

5. Why is casting not an option for you?

Answer 2

Unless I'm missing something, change the signature of the method to take a double .

public static short DigitsBeforeDot(double x) {
    short a = (short) (Math.log10(x) + 1);
    System.out.println(a);
    return a;
}

Also, it seems really counter productive to pass a float or a double only to cast to a short .