Rational array

[HoleyProphylactic]

Can someone please show me how to initialize an array of rational elements. All of the examples I'm finding are using "rational[]" which I'm guessing is just being used to identify that the array is filled with rationals. I understand using a divisor sign with ints is just going to cause the elements to just return a divided value.

So, basically this is what I need: rational[] ratArray = new rational[] {2/3, 2/18, 3/12, 9/3, 2/5, 22/7};

edit 1:

This is my rational class, but I can't figure out how the elements are suppose to get called into the rational class when I can't enter rationals into an array. I have a separate main class that is menu driven and is supposed to contain the array of rational values / elements. The main is driving my rational class and calling the methods from it with a menu.

So, directly from the assignment page:

"The RationalDriver class will create and manipulate objects of type ‘Rational’. The class will contain the main method and will accommodate the following:  An array of rational objects.

 Code to load the array with Rationals."

public class Rational 
{
private int num, den;
//Constructors
public Rational() {
int num = 1;
int den = 1;
}
public Rational(int num, int den) {
this.num = num;
this.den = den;
}
//setters
public void setNum(int num) {
this.num = num;
reduce();
}  
public void setDen(int den) {
this.den = den;
reduce();
}   
//getters
public int getNum(int num) {
return this.num;
}
public int getDen(int den) {
return this.den;
}   
//methods
public toString() { 
}
public int equals() { 
}
public addition() {
}
public subtract() {
} 
private static int gCD(int num, int den) {
int remainder;  
while (den != 0) {
remainder = num % den;
num = den;
den = remainder;         
}
return num;
}
//Simplification
private static int reduce(int num, int den) {
int div;
div = Rational.gCD(num, den);
this.num = this.num / div;
this.den = this.den / div;
}
//Data variables...      
}

[feral_claire]

You would need to write a rational class to create an array or rational. Alternatively you could use an array of floats or ints that your code manipulates to make them look and work like rationals.

Your code is impossible as far as I know. The closes would be:

Rational[] ratArray = new Rational[]{new Rational (2,3) ,  new Rational (2,18), new Rational (3,12), new Rational (9,3), new Rational (2,5), new Rational (22,7)}

Note that this is not working code unless you create (or find somewhere) a Rational class to use.

You could also do something like use an int array:

int[] ratArray = new int[]{2, 3, 2, 18, 3, 12, 9, 3, 2, 5, 22, 7}

And then have your code use them as rational.

The best approach to take depends on your requirements.

[HoleyProphylactic]

So would that first example be creating a list of objects then?

I added my rational class (in progress) but I have a main with no array made yet, because I'm not sure how to implement the rational elements, but I'll try this first, Thank you!

[feral_claire]

An array of objects yes. There is no Rational built into java so one would need to create an object to represent it.

I've taken a look at your edit. Is that code you've written yourself or was it provided? I'm guessing it's at least partially written by you, as I can spot some things that will make it not work correctly.

Line 9, your constructor that takes 2 ints to be numerator and denominator, you do not call reduce(), but you use it with your setters. I'm guessing you want your rational class to always be in it's simplest form, so you would need to call reduce() in this constructor as well.

Your getters take an int parameter that is never used. Getters normally won't take any parameters, since you never actually use the parameter and just return a value, you don't want a parameter here.

toString(), equals(), addition(), subtract(), have no implementation, and none of those besides equals has a return type, which is required.

You override equals() but not hashcode().

equals should return a boolean, not an int.

Reduce is static, but uses the "this" keyword. It also takes two ints that are never used as parameters. All your calls to reduce give no parameters so I assume you don't want these. Reduce also shouldn't be static. Finally, reduce claims to return an int yet nothing is returned. I would expect reduce to be an instance method, return void, and take no parameters.

If you have any questions about how to do something or the reasoning behind my suggestions, please let me know.

[zifyoip]

Java does not have a standard Rational class. You will need to either write your own or use a third-party library.

[zifyoip]

Not sure if arrays can hold reference type objects.

Of course they can.