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Program that removes duplicated elements and return its new elements and size

My code is almost done but the problem is the returning size it supposed to return the size after the duplicated elements has been removed. it wont output the right size.
import java.util.Scanner;
import java.util.Arrays;
public class Main
{
public static void main (String[] args)
{
int size;
int i;
int j;
Scanner scn = new Scanner(System.in);
System.out.print("Enter the number of elements: ");
size = scn.nextInt();
System.out.println("\n");
int myArray[] = new int [size];
for(i = 0; i < size; i++)
{
System.out.print("Enter value for num["+i+"]: ");
myArray[i] = scn.nextInt();
}
System.out.print("\nThe inputted values are ");
for(i = 0; i < size; i++)
{
System.out.print(" " + myArray[i] + ",");
}
System.out.print("\nDuplicate values ");
for (i = 0; i < myArray.length-1; i++)
{
for (j = i+1; j < myArray.length; j++)
{
if ((myArray[i] == myArray[j]) && (i != j))
{
System.out.print(" " +myArray[j]+ ",");
}
}
}
int length = myArray.length;
length = remove_dupli(myArray,length);
System.out.print("\nThe new values of the array are ");
for(i = 0; i < length; i++)
{
System.out.print(" " +myArray[i]+", ");
}
System.out.println("\nThe new length of the array is: "+array_sort(myArray));
}
is there a problem on this part?
public static int remove_dupli(int myArray[], int n){
if (n==0 || n==1){
return n;
}
int[] temp = new int[n];
int j = 0;
for (int i=0; i<n-1; i++){
if (myArray[i] != myArray[i+1]){
temp[j++] = myArray[i];
}
}
temp[j++] = myArray[n-1];
for (int i=0; i<j; i++){
myArray[i] = temp[i];
}
return j;
}
or this part?
public static int array_sort(int[] myArray) {
int index = 1;
for (int i = 1; i < myArray.length; i++) {
if (myArray[i] != myArray[index-1])
myArray[index++] = myArray[i];
}
return index;
}
}
The output should be:
Enter Number of Elements: 4
Enter value for num[0]: 2
Enter value for num[1]: 2
Enter value for num[2]: 3
Enter value for num[3]: 4
The inputted values are 2,2,3,4
Duplicated values 2,
The new values of the array are 2,3,4
The new length of the array is 3

The process you are using to find the duplicate elements is fine but you are not actually changing the elements in the array , you are just printing the non-duplicate ones, best approach is to change the value of the duplicate elements as a flag and then to find the length of the array after the duplicates have been removed,it will be easy :
for(int i=0;i<array.length;i++){
for(int j=i+1;j<array.length;j++)
{
if((array[i]==array[j]) && i!=j)
System.out.println("duplicate value:"array[j]);
array[j]=-1;
}
}
So, now for the array length after removing the duplicate elements is:
int count=0;
for(int i=0;i<array.length;i++){
if(array[i]!=-1)
count ++;
}

How does this code that fills an array with 10 distinct random numbers work?

Can someone please explain the thought process behind this code? I am kind of confused on how it works. This is the question that the code is addressing:
Write code (using one or more loops) to fill an array "a" with 10 different random numbers between 1 and 10.
Thank you so much for any help!
public static void main(String[] args){
//R8.8
int a[] = new int[10];
Random randomGenerator = new Random();
for (int i = 0; i < a.length; i++){
a[i] = 1 + randomGenerator.nextInt(100);
}
for (int i = 0; i < a.length; i++) {
int number = 1 + randomGenerator.nextInt(100);
int count = 0;
for (int j = 0; j < i; j++) {
if (a[j] == number) {
count += 1;
}
}
if (count > 0) i -= 1;
else a[i] = number;
}
}
}

See my comments in the code itself:
public static void main(String[] args){
//make a new array of 10 integers
int a[] = new int[10];
//declare an object which we can use to generate random numbers
//this object probably uses the system time to generate numbers that appear random
//but at the end of the day, java does it for us so
//we don't really need to know or care how it generates random numbers
Random randomGenerator = new Random();
//loop over each element in our array
for (int i = 0; i < a.length; i++){
//for each element, set that element to a random between 1 and 100 inclusive
//nextInt(x) gets a number between 0 (inclusive) and x (not inclusive)
//so to translate that to 1 to x inclusive, we need to add 1 to the result
a[i] = 1 + randomGenerator.nextInt(100);
}
//everything below here does literally nothing to solve the problem
//everything you need to fill the array with random numbers is above
for (int i = 0; i < a.length; i++) {
int number = 1 + randomGenerator.nextInt(100);
int count = 0;
for (int j = 0; j < i; j++) {
if (a[j] == number) {
count += 1;
}
}
if (count > 0) i -= 1;
else a[i] = number;
}
}
}
Please note that you should use 1 + randomGenerator.nextInt(10); to fill the array with numbers between 1 and 10, not 1 + randomGenerator.nextInt(100);.

Finding the largest number in a column using 2D arrays

I was trying to write a method that finds the largest number in a column. However, it seems that I am having problem to find a way to return the highest number in a column rather than taking into consideration all numbers combined in the array. I would really appreciate any comments or feedback!
This is my code:
public static void max1(int[][] score) {
for (int i = 0; i < score.length; i++) {
int max = score[0][0];
for (int j = 0; j < score[i].length; j++)
if (score[i][j] > max)
max = score[i][j];
System.out.println(max + " ");
}
}

You are trying to find the max in row not in column. Do some changes in your code
public static void max1(int[][] score) {
for (int i = 0; i < score[0].length; i++) { // i should be your column
int max = score[0][i];// assign 1st value of the column as max
for (int j = 0; j < score.length; j++){ // j is your row
if (score[j][i] > max){ // check the column elements instead of row elements
max = score[j][i];// get the column values
}
}
System.out.println(max + " ");
}
}

Do int max = score[0][i]; instead of int max = score[0][0]; Because if you always intialize max with score[0][0] and this int is bigger then the biggest value in a column, you will get a wrong result.
And do:
if (score[innerloop][outerloop] > max)
max = score[innerloop][outerloop];
instead of:
if (score[outerloop][innerloop] > max)
max = score[outerloop][innerloop];
That was logical failure because the first index is the column and the secound is the row.
score[0][0] = 1;
score[0][1] = 2;
score[0][2] = 3;
score[1][0] = 4;
score[1][1] = 5;
score[1][2] = 6;
score[2][0] = 7;
score[2][1] = 8;
score[2][2] = 9;
The Array now look like this matrix:
1 2 3
4 5 6
7 8 9
You want compare for example 1,4,7 so you habe to compare score[0][0], score[0][1], score[0][2]. So the secound index must be the counter of the inner for-loop.

You need to specify the index of the column you want to find the max in and loop on rows:
public static int maxCol(int [][] score, int colIndex) {
int max = score[0][colIndex];
for(int i = 0 ; i < score.length ; ++i) {
max = Math.max(max, score[i][colIndex]);
}
return max;
}

public static void max1(int[][] score) {
for (int i = 0; i < score.length; i++) {
int max = -1;
for (int j = 0; j < score[i].length; j++)
if (score[i][j] > max)
max = score[i][j];
System.out.println("max: '" + max + "'");
}
}
And perhaps you switched your columns and rows, means you have to switch the code too, happened already a lot to me. Try to check if i is your rows and j is your columns.

The following code prints the Maximum Number in each column.
public static void max1(int[][] score) {
for (int i = 0; i < score.length; i++) {
int max = Integer.MIN_VALUE; // set max to minimum value before starting loop
for (int j = 0; j < score[i].length; j++)
{
if (score[i][j] > max)
max = score[i][j];
}
System.out.println(max + " ");
}
}

First you should change the int max = score[0][0]; into as int max = Integer.MIN_VALUE; as it might produce not valid result.
And the second is that you need to swap the index while compare
if (score[j][i] > max) {
max = score[j][i];
}

static int max1(int[][] score) {
int max = score[0][0]; // set initial value to the first index in array
for (int i = 0; i < score.length; i++) { // cycle through row
for (int j = 0; j < score[i].length; j++) { // cycle through colmn
if (score[i][j] > max) { // if the index value is greater than largest number
max = score[i][j]; // make it the new index value
}
}
} return max;
}

Fill double array with random numbers and then print even and odd numbers from that array

So here's my problem. I have to write a program that will fill array with random numbers(and it's ok), then it's necessary to print only even index numbers or only odd value numbers(j). Tried like this but when i put if statement and it shows every even number (index and value-the second in array) so it wrong. What should i do so?
import java.util.Random;
public class Array {
public static void main(String[] args)
{
int rows = 5;
int colu = 2;
Random r = new Random();
int [][] array = new int [rows][colu];
for(int row = 0; row < array.length; row++)
{
for(int col = 0; col < array[row].length; col++)
{
array[row][col] = r.nextInt(10);
}
}
for(int i = 0; i < array.length; i++)
{
for(int j = 0; j < array[i].length; j++)
{
if(array[i][j]%2 == 0){
System.out.print(array[i][j] + " ");
}
}
}
System.out.println();
}
}
Thanks

I'm going to take a stab at this but I'm not sure if I quite understand yet.
int array[][] = new int[row][col];
// ... populate the array with random numbers, works fine...
// Let's traverse the first column.
for (int i = 0; i < row; i++) {
int value = array[i][0]; // col 0 means first column
if (value % 2 == 0) {
// ...
}
}
// Let's traverse the second column.
for (int i = 0; i < row; i++) {
int value = array[i][1]; // col 1 means second column
// ...
}
Is this what you mean? If it is, do you see the pattern and how you could generalize this and make the code a bit smaller?

Just implement this formula in your "if" statement :
(Number × 2 )/4 ==0. You will always get even numbers. You can handle the rest :D

Sorting with 2D Arrays

I need help with sorting Random numbers into a 2D array. I have to generate 50 random numbers into a column of the array, then sort the numbers in order (ascending or descending). This is what I have so far and am so lost. Please Help.
UPDATED VERSION
public static void main(String[] args)
{
int rows = 2;
int columns = 50;
int[][] anArray = new int[rows][columns];
Random rand = new Random();
for (int i = 0; i < anArray.length; i++)
{
for (int j = 0; j < anArray[0].length; j++)
{
int n = rand.nextInt(100);
anArray[i][j] = n;
}
}
int []temp;
for (int i=0;i<anArray.length;i++)
{
for (int j=0;j<anArray.length-i;j++ )
{
if (anArray[i][j]>anArray[i][j+1])
{
temp =anArray[j];
anArray[j+1]=anArray[j];
anArray[j+1]=temp;
}
}
}
for (int i = 0; i < anArray.length; i++)
{
for (int j=0;j<anArray.length-i;j++ )
{
System.out.println(anArray[i][j]);
}
}
}
}

You can sort 2D arrays on their initial element using a custom Comparator:
Arrays.sort(anArray, new Comparator<int[]>() {
public int compare(int[] lhs, int[] rhs) {
return lhs[0]-rhs[0];
}
});

First of all, you need nested for loops in order to properly insert the random numbers into the two dimensional array. I have also updated my response to show how the sorting should be done. Hope this helps!
EDITED TO SATISFY REQUIREMENTS MENTIONED IN COMMENT BELOW.
import java.util.Arrays;
import java.util.Random;
public class Test {
/**
* #param args
*/
public static void main(String[] args) {
int rows = 2;
int columns = 50;
int[][] anArray = new int[rows][columns];
Random rand = new Random();
//initialize the first row only
for (int j = 0; j < anArray[0].length; j++)
{
int n = rand.nextInt(100);
anArray[0][j] = n;
}
System.out.println("-----------Before the Sort----------------");
for (int i = 0; i < anArray.length; i++)
{
for (int j = 0; j < anArray[0].length; j++)
{
System.out.print(anArray[i][j] + ", "); //format any way you want
}
System.out.println(); //to make each row print on a new line.
}
anArray = mySort(anArray);
System.out.println("-----------After the Sort----------------");
for (int i = 0; i < anArray.length; i++)
{
for (int j = 0; j < anArray[0].length; j++)
{
System.out.print(anArray[i][j] + ", "); //format any way you want
}
System.out.println(); //to make each row print on a new line.
}
}
private static int[][] mySort(int[][] anArray) {
int [][] result = new int[anArray.length][anArray[0].length];
int thisRow[] = getRow(anArray, 0);
Arrays.sort(thisRow);
for(int j = 0; j < thisRow.length; j++){
result[0][j] = anArray[0][j];
result[1][j] = thisRow[j];
}
return result;
}
private static int[] getRow(int[][] anArray, int row) {
int thisRow[] = new int[anArray[row].length];
for(int j = 0; j < anArray[row].length; j++){
thisRow[j] = anArray[row][j];
}
return thisRow;
}
}

You can sort by considering the 2D array 1D. Let's consider a 3x4 array.
1st element's index is 0, 2nd is 1, 3rd is 2, 4th is 3, 5th is 4, etc.
General formula to convert from a 1D index to a 2D:
row_index = _1D_index % nRows;
col_index = _1D_index % nCols;
For example the 5th element has the 1D index of 4, to get the row: 4 % 3 = 1, to get the col, 4 % 4 = 0, so your element is at 1,0. What's the point of all this? Now you can just make a function
int GetAt(int index)
{
return array[index % nRows][index % nCols];
}
and something along the lines of:
void Swap(int index1, int index2)
{
int r1 = index1 % nRows;
int c1 = index1 % nCols;
int r2 = index2 % nRows;
int c2 = index2 % nCols;
int temp = array[r1][c1];
array[r1][c1] = array[r2][c2];
array[r2][c2] = temp;
}
And sort the array as if it was one dimensional :)