Java comparing array element index to index

Question

Here's my code:

public static void main(String[] args) {

    int lotteryNumbers[] = new int[5];
    int playersNumbers[] = new int[5];
    int winNum = 0;


    Scanner in = new Scanner(System.in);
    Random r = new Random();
    // array med 5 heltal

    //skapa en for loop som fyller upp arrrayen
    //med slumpade tal från klassen Random
    for (int i = 0; i < lotteryNumbers.length; i++) {
        lotteryNumbers[i] = 0 + r.nextInt(9);
        System.out.print(lotteryNumbers[i] + "\t");

    }
    System.out.println();

    for (int i = 0; i < playersNumbers.length; i++) {
        //System.out.println("Var god ange ett nummer mellan 0-9: ");
        //playersNumbers[i]=in.nextInt();
        playersNumbers[i] = 0 + r.nextInt(9);

    }
    for (int i = 0; i < playersNumbers.length; i++) {

        System.out.print(playersNumbers[i] + "\t");

    }
    System.out.println();

    if (lotteryNumbers[0]==playersNumbers[0])
         winNum++;
         if (lotteryNumbers[1]==playersNumbers[1])
              winNum++;
              if (lotteryNumbers[2]==playersNumbers[2])
                   winNum++;
                   if (lotteryNumbers[3]==playersNumbers[3])
                        winNum++;
                        if (lotteryNumbers[4]==playersNumbers[4])
                            winNum++;

     System.out.println("You have " + winNum + " winning numbers");

}

}

I need to compare the numbers index to index. As you can see I have 5 if statements. I was wondering if I can do this with a loop instead?

I already tried to do as this:

for (int i = 0; i < lotteryNumbers.length; i++) {

        for (int j = 0; j < playersNumbers.length; j++) {

       if (lotteryNumbers[i] == playersNumbers[j]) {
                winNum++;

            }
        }
    }

But this compares every index with every index, not just index to index. I want to know how to write a loop for compare index to index?

Use one loop, not two.

Biffen
– Biffen

2015-02-12 07:53:21 +00:00
Commented Feb 12, 2015 at 7:53 — Biffen
– Biffen, Commented Feb 12, 2015 at 7:53

colavitam · Accepted Answer · 2015-02-12 07:52:53Z

2

Only use one loop. That way the same index can be used across the two arrays.

for (int i = 0; i < lotteryNumbers.length; i++) {
    if (lotteryNumbers[i] == playersNumbers[i]) {
            winNum++;
    }
}

answered Feb 12, 2015 at 7:52

colavitam

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Comments

T.J. Crowder · Accepted Answer · 2015-02-12 07:53:12Z

1

You're working too hard. :-) Just one loop, not two, and use the same index variable with both arrays:

for (int i = 0; i < lotteryNumbers.length; i++) {
    if (lotteryNumbers[i] == playersNumbers[i]) {
        winNum++;
    }
}

answered Feb 12, 2015 at 7:53

T.J. Crowder

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3 Comments

Tapani Yrjölä Over a year ago

I realized I could do it with enhanced for loop

T.J. Crowder Over a year ago

@TapaniYrjölä: The enhanced for loop doesn't help you here.

Tapani Yrjölä Over a year ago

I realized that when I tried. Your answer is the right one

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