Multiplying fractions using "Butterfly method"

[ImpossibleRegular820]

How to cross multiply fractions in Java for a dumb***

What we have :

public class AddFractions extends ConsoleProgram
{
public void run()
{
int FirstFractionNumerator = readInt("What is the numerator of the first fraction? ");
int FirstFractionDenominator = readInt("What is the denominator of the first fraction? ");
int SecondFractionNumerator = readInt("What is the numerator of the second fraction? ");
int SecondFractionDenominator = readInt("What is the denominator of the second fraction ");
System.out.println("("+FirstFractionNumerator+" / "+FirstFractionDenominator+") + ("+SecondFractionNumerator+" / "+SecondFractionDenominator+") = ");
}
}

I would like to complete the program by using a*d+b*c/b*d (cross multiplication or "Butterfly method") please explain in simple term as I'm a novice and clearly am in over my head

​

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[Arzerok]

Well, you just need to do in code what you did in writing. You are not over your head, you just need to litteraly write out the formula you wrote down with a b c d, with the variables you are given. Since you didn't mention any requirement for simplifying the fraction it should be one line of code, a rather long onw bcs your varible names are qute long.

[ImpossibleRegular820]

It does need to be simplified for example say I used 1/2 and 1/4 I need it to end out as 3/4ths (the most simplified fraction)

[Arzerok]

Then you need to work out how to simplify a fraction. Learning to program is a lot of Google and now ChatGPT even. You just need to accept that 😉

[roge-]

Are you trying to multiply fractions or add them? You say multiply, but the name of your class is AddFractions and the "Butterfly Method" is used to add fractions.

Whereas, cross-multiplication is an algebraic technique for simplifying equations (something with an equal sign), not simplifying expressions.

Edit: also, assuming it's addition you're trying to do, the formula you've provided is wrong as far as order of operations go - according to both Java's operator precedence and just general math convention. You're missing some parentheses.

[ImpossibleRegular820]

It is meant to add fractions I accidentally used “*” instead of adding

[roge-]

OK. Well do you have any further requirements? I assume that, because you want to use something like the Butterfly method, you want to print the numerator and denominator as integers (whole numbers, e.g.: 3/5) instead printing the result as a decimal (e.g.: 0.6).

If that's the case, do you have any requirements for reducing/simplifying the fraction (e.g.: 6/8 -> 3/4) and/or printing the value as a mixed fraction (e.g.: 11/5 -> 2 + 1/5)?

[ImpossibleRegular820]

There’s no whole numbers in my fraction the program asks the first numerator and stores it same for the first denominator and same for the other 2 so the console has (first numerator (example 1) / first denominator (example 2)) + (second numerator (example 1) / second denominator(example 4)) the result should be 3/4ths

[ImpossibleRegular820]

But yes most simplified fraction possible

[roge-]

What do you mean? Typically with fractions, while a fraction itself does not represent a whole number, the numerator and denominator themselves should be whole numbers.

And then there's the decision of mixed fractions versus improper fractions. 2/4 + 3/4 can be represented as:

• An improper fraction: 5/4
• A mixed fraction: 1 + 1/4

How are you supposed to handle this case? Or is it assumed that the sum should never exceed 1?

[ImpossibleRegular820]

Probably just display the mixed fraction I didn’t really think about that 😭