How to get the top 5 numbers from a 2D array of random numbers

I am pretty new to java and am just learning 2D arrays. I am trying to get the top 5 numbers to display from a random list. I think this could work but am not sure why I am getting an error. One other thing is that I cannot use the sort function.

Code here:

public static void main(String[] args) {
//Random Number stuff
Random rand = new Random();
int[] large = new int [5];
int max = 0, index;
int[][] arrSize = new int [4][5];
for (int i = 0; i < arrSize.length; i++) {
for (int j=0; j< arrSize[i].length; j++) {
arrSize[i][j] = rand.nextInt(89) + 10;
System.out.print(arrSize[i][j] + " ");
}
System.out.println();
}
// Top 5
for (int p = 0; p < 5; p++) {
max = arrSize [0][0];
index = 0;
for (int i = 0; i < arrSize.length; i++) {
for (int j = 0; j < arrSize[i].length; j++) {
if (max < arrSize[i][j]) {
max = arrSize[i][j];
index = i;
}
}
}
large
 = max;
arrSize[index] = Integer.MIN_VALUE;  //Error here
System.out.println("Highest Number: " + large
);
}
}
}

Error text:

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
Type mismatch: cannot convert from int to int[]
at secondAssignment.BiggestNumbersRectangular.main(BiggestNumbersRectangular.java:47)

I am not sure why I am getting an error, any help would appreciated. If anyone else has any answers for how I could get the top 5 in a different way that would also be appreciated.

You declare your arrSize here

int[][] arrSize = new int [4][5];

and try to set it's value here

arrSize[index] = Integer.MIN_VALUE;

The Object at arrSize[index] is an array.

Remember that a 2D array basically looks like this:

arrSize
- arrSize[0]
- arrSize[0][0]
- arrSize[0][1]
- arrSize[1]
- arrSize[1][0]
- arrSize[1][1]
- arrSize[2]
- arrSize[2][0]
- arrSize[2][1]
- arrSize[3]
- arrSize[3][0]
- arrSize[3][1]

Because index is a single int, you are assentially calling arrSize[0], which contains arrSize[0][0] and arrSize[0][1].

The Integer.MIN_VALUE is not an array of integers. It is an int. You cannot assign int to int[].

As you can see in other parts of the code, to access values in 2D array arrSize, you need 2 indexes in your case (and usually) i and j.

You need to save both i and j after you find the highest number.

if (max < arrSize[i][j]) {
max = arrSize[i][j];
indexI = i;
indexJ = j;
}

and then

arrSize[indexI][indexJ] = Integer.MIN_VALUE;

As to why you got the error, arrSize[i] gets you a 1D array. It's still an array and you cannot set an array to an integer (Integer.MIN_VALUE). in Java represented as int[] in the error message.

The algorithm could be improved, instead of using a single integer max for saving the highest value, you could use a maxArr of the same size as the number of highest numbers you want (in your case 5) and check against all of the numbers in maxArr using a for in place of

if (max < arrSize[i][j]) {
max = arrSize[i][j];
index = i;
}

That would mean you could remove the index (or indexI and indexJ) and topmost for cycle (for (int p = 0; p < 5; p++)). But that's another topic, and one you should learn yourself.