CODEWITHSUNDEEP
javaarraysmath
Rhendz
Rhendz

Reputation: 101

How can I translate indexes that are odd to an index {0,1,2,3,4,5}?

public static int[] Separator1() {
    for (int i = 0; i < numbersGenerated.length; i++) {
        if (i % 2 == 0) {
            numberSet1[i / 2] = numbersGenerated[i];
        }

    }
    return numberSet1;
}

public static int[] Separator2() {
    for (int i = 0; i < numbersGenerated.length; i++) {
        if (i % 2 == 1) {
            numberSet2[i / 2] = numbersGenerated[i];
        }

    }
    return numberSet2;
}

In the code above, I can successfully produce indexes from even numbers for numberSet1, but when I try to produce indexes for numberSet2 I cannot. The reason I cannot produce indexes for that array is because the numbers are odd. The [i / 2] is just a place holder by the way because I have no idea what formula I could use to produce the indexes.

Example for Separator1: numbersGenerated = {10,20,30,40,50,60,70,80,90,100};

numberSet1 would return values of {10,30,50,70,90}

I want numberSet2 to return values of {20,40,60,80,100}

I am open to any suggestions because earlier I was actually trying to use one Separator and return 2 values from it and I found out that it would not work. The code just needs to be able to separate an array into 2 distinctive arrays with the same values from the first one.

Thank You, for your time :D

Upvotes: 1

Views: 155

Answers (2)

Chad
Chad

Reputation: 168

I am pretty new to this and I would love for someone to give us an explanation why yours did not work. I thought i/2 by integer math would round down to the nearest integer. but give this a try.

public static int[] Separator2() {
int counter = 0;
for (int i = 0; i < numbersGenerated.length; i++) {
    if (i % 2 == 1) {
        numberSet2[counter] = numbersGenerated[i];
        counter++;
    }

}
return numberSet2;

Upvotes: 0

Andrew_CS
Andrew_CS

Reputation: 2560

I believe you're wanting to put numbers from even indexes into one collection and numbers from odd indexes into a separate collection. Example - indexes 0, 2, 4, 6, ... are returned from Seperator1, and indexes 1, 3, 5, 7, ... are returned from Seperator2.

Here is the basic logic.

public static int[] Separator1() {
    for(int i = 0; i < numbersGenerated.length; i++) {
        if (i % 2 == 0) { // Grabs even numbered indexes
            numberSet1[i / 2] = numbersGenerated[i]; // Places even numbered indexes
        }
    }
    return numberSet1;
}

public static int[] Separator2() {
    for (int i = 0; i < numbersGenerated.length; i++) {
        if (i % 2 != 0) { // Odd numbered indexes
            numberSet2[(i - 1) / 2] = numbersGenerated[i]; // Places odd numbered indexes
        }
    }
    return numberSet2;
}

(i - 1) / 2 Example: 

For index 1 | ((1 - 1) / 2) = 0
For index 3 | ((3 - 1) / 2) = 1
For index 5 | ((5 - 1) / 2) = 2
....

You might want to consider renaming the methods to something like getEvenIndexes and getOddIndexes in the future to avoid confusion.

Side Note: Java convention has method names start with a lowercase letter - this will make it easier for other people to read your code.

Upvotes: 1

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