So, I'm working on a project right now, and I'm confused on how you would convert a decimal value (say .333333) to a fraction(1/3)

I've looked it up for a while on Google and haven't really been able to get a straight forward answer that I really understand...

Is there a simple way of doing this?


Example for the different situations I would need to solve:

1/3 + 4/5

3/4 - 6/7

4/5 * 3/5

5/6 / 4/5

Honestly, I'm sort of lost on this. I didn't think it would be too difficult, and maybe it isn't but I'm not seeing it

you asked about converting decimals to fractions, but the problem you need to solve are just fraction arithmetic. can you explain what converting decimals to fractions has to do with fraction arithmetic?

/edit: risking stating the obvious:
to add/subtract fractions, create a common denominator and add/subtract the numerator.
to multiply fractions, multiply the numerator and denominator.
to divide fractions, flip the numerator/denominator of the second and multiply.
reduce at the end.

This post was edited by carteblanche on Nov 7 2014 07:04pm

You just multiply by which fraction you want.

0.333333333 * 3 is .999999999 (1/3)

0.333333333 * 5 is 1.6666666 (2/5)

This is a very loose way to convert fractions.

As for fraction math just use bedmas in the interpreter/compiler:



so the answer would be 17/15 or 1 and 2/15

Now of course most answers will not be clean like this.

This post was edited by AbDuCt on Nov 7 2014 07:03pm

Are you reading the expression from console?

In that case are you reading in num1, den1, num2, den2, doing num1/den1 to get decimal value dec1, then num2/den2 to get dec2, then doing dec1 + dec2 = sum, and Now you want to convert sum to a fraction?

If this is what you are doing, then stop it.

You have the parts of the fraction read in. You don't need to convert to a decimal.

Multiply num1 with den2 to get num3. Multiply num2 with den1 to get num4. Add these together to get num5.
Multiply den1 and den2 together to get den3.

Find the gcd of num5 and den3.
Divide num5 by gcd to get resultNumerator
Divide den3 by gcd to get resultDenominator

You have successfully added two fractions together.

And yes, I used confusing variable names for maximum confusion.

This is basically what I need lol

But, how would I find the GCD of a dynamic input? (could be any fraction inputted by the user)
Lol, I haven't had to do this type of math in Java before, so it's really new to me; finding GCD and all of a dynamically inputted fraction.

This post was edited by DD_Rocking on Nov 7 2014 07:28pm

The same way you would find the gcd of any 2 numbers. With euclid's algorithm:

So, this is basically as long as b != 0, it will continuously call the same method with the parameters of b, and a modulus b until b is 0?

I'm looking at some examples and looks like that but I'm not sure...

Let's reduce 12/40

a = 12, b = 40

gcd(12,40) = gcd(40,12%40=12) = gcd(12, 40%12=4) = gcd(4, 12%4=0) = 4

12/4 = 3

40/4 = 10

3/10

This post was edited by Minkomonster on Nov 7 2014 08:30pm

So would this gcd method sort of look like:



So this method basically keeps flipping the parameters and using modulus to eventually get the denominator to 0, and once that occurs, it returns the numerator value?

Your method is equivalent to mine. You just expanded the ternary operator and gave it meaningful variable names.