CODEWITHSUNDEEP
javaarraysrotation2d
user3476554
user3476554

Reputation:

How do I get this 2D Array to rotate to the right 90 degrees?

So I have a 2D array, and it is supposed to rotate to the right 90 degrees, but instead it rotates to the left. Really can't figure out why

public class CrackCode16 {

public static void main (String args[]){
    int [] [] oldarray = new int [3][3];

    int value = 1;

    for (int i = 0; i < 3; i++){
        for (int j =0; j<3; j++){
            oldarray[i][j] = value;
            value++;
        }
    }


    for (int i = 0; i < 3; i++){
        for (int j =0; j<3; j++){
            System.out.print(oldarray[i][j] + "\t");
        }
        System.out.println("");
    }


    oldarray = rotate(oldarray, 3);


    System.out.println("");
    for (int i = 0; i < 3; i++){
        for (int j =0; j<3; j++){
            System.out.print(oldarray[i][j] + "\t");
        }
        System.out.println("");
    }

}

public static int [][] rotate (int [][] passedIn, int n){

    int [][] newarray = new int [n][n];

    for (int i = 0; i < n; i++){
        for (int j =0; j<n; j++){
            newarray[i][j] = passedIn [j][n-1-i];
        }
    }   

    return newarray;
}

}

Output:

1 2 3
4 5 6
7 8 9

3 6 9
2 5 8
1 4 7

Upvotes: 2

Views: 3860

Answers (1)

ifloop
ifloop

Reputation: 8386

newArray[i][j] = passedIn [n-1-j][i];

instead of 

newarray[i][j] = passedIn [j][n-1-i];

Additionally, when working with Java8, you might consider using a Stream to print your array:

Stream.of(oldarray).forEach(e -> System.out.println(Arrays.toString(e)));

Upvotes: 1

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