Find and search for a double in an array and return its indices? Is this an array element swap method?)

java

Solution

A few things to fix in your first example:

Right now, `j < circles[0].length` means that only one column is being searched: column `0`. You'll want `j < circles[i].length` to search every column by row.

`if (temp == r)` means you're comparing a `Circle` and a `double`. I'm not familiar with the circle class, but I believe you'll want to replace instead of `Circle temp = circles[i][j]` with `double temp = circles[i][j].getRadius();`.

You want to return as soon as you find the matching `Circle`, so you have some things a little backwards. With my new revisions, `if (temp == r)` will now activate the code if you have found the correct radius. That means below that `if` statement, you'll want `return {i, j};`. That will return the current circle's (which has the correct radius) indicies.

The last statement will be called if none of the radius tests return true, so where you have `return circles.indexOf(r);`, you'll want `return {-1, -1};`.

Since arrays are 0-based, and less than already means one minus the value, you do not need `- 1` in `i < circles.length - 1`

On your second example:

Your `findCircleWithRadius` method has two paramaters: a `Circle[][]` and a `double`. That means you'll need to give it those. The method you created is not called from a double, as well, so you can't say `r1.findCircleWithRadius();` Additionally, you need to use the `int[]` that the `findCircleWithRadius` passes you to get those `Circle`'s. Therefore, your first lines in `swapCircles` should be:

int[] rad1 = this.findCircleWithRadius(circles, r1); // Get the coordinates of the first circle by passing the 2D array, and the radius you're looking for.
int[] rad2 = this.findCircleWithRadius(circles, r2); // Get the coordinates of the second circle by passing the 2D array, and the radius you're looking for.

Circle radius1 = circles[rad1[0]][rad1[1]]; // Circle 1 is equal to the Circle in the array that has coordinates of the first index in the coordinates, and the second index of the coordinates. (circles[x, y])
Circle radius2 = circles[rad2[0]][rad2[1]]; // Circle 2 is equal to the Circle in the array that has coordinates of the first index in the coordinates, and the second index of the coordinates. (circles[x, y])

In conclusion, the completed code with my revisions will be as follows:

public int[] void findCircleWithRadius(Circle[][] circles, double r) {

for(int i = 0; i < circles.length; i++) { //search the row
    for(int j = 0; j < circles[i].length; j++) { //search each column
        double temp = circles[i][j].getRadius();
        if(temp == r)
        return {i, j};
    }
 }
 return {-1, -1};
 }

public static void swapCircles(Circles[][] circles, double r1, double r2) {

int[] rad1 = this.findCircleWithRadius(circles, r1);
int[] rad2 = this.findCircleWithRadius(circles, r2);
Circle radius1 = circles[rad1[0]][rad1[1]];
Circle radius2 = circles[rad2[0]][rad2[1]];

Circle temp2 = radius2;

radius2 = radius1;
radius1 = temp2;
}

Otherwise, everything else is looking pretty good! I hope you did well on your quiz! Please let me know if you have any further questions about anything I have said so I can make sure you understand this fully.

Problem

Original source