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How to create a method in java which prints out the elements of a matrix in shown pattern?

The contents of the matrix starts from 1 to the product of rows and columns. The method "scan" should print out as per following:
If the row is entered 4 and column is entered 7, the contents of the matrix should look like the image provided here:
the correct matrix
So far I have tried absolutely noting because I just don't know how to make this possible. I can print in zigzag, spiral but I just have no idea about this one. Please have mercy on me and grant me an insight.
This code currently prints out in a spiral pattern.
How should I modify this "scan" method so it satisfies the aforementioned condition?
import java.util.Scanner;
import java.util.Random;
public class that {
public static void main(String[] args) {
int range;
range = 100;
Scanner scn = new Scanner(System.in);
while(true) {
int m, n;
System.out.println("Enter the number of row: ");
m = scn.nextInt();
System.out.println("Enter the number of column: ");
n = scn.nextInt();
if(m <= 0||n <= 0) break;
int[][] tab = new int[m][n];
generate(tab, range);
scan(tab);
}
scn.close();
}
static int len(int x) { return (""+x).length(); }
static void generate(int[][] tab, int range) {
// Random generation
Random rg = new Random();
for(int i=0; i<tab.length; ++i)
for(int j=0; j<tab[0].length; ++j)
tab[i][j] = rg.nextInt(2*range) - range;
}
static void scan(int[][] tab) {
int m = tab.length;
int n = tab[0].length;
int totalWidth = 0;
int num = 1;
int rowStart = m - 1, rowEnd = 0, colStart = 0, colEnd = n - 1;
// Compute column widths
int[] colw = new int[n];
for(int j=0; j<n; ++j) { // For every column look down
colw[j] = len(j); // (""+j).length();
for(int i=0; i<m; ++i) {
int w = len(tab[i][j]); //("" + tab[i][j]).length();
if(w > colw[j]) colw[j] = w;
}
totalWidth += colw[j];
}
// Printing
int ris = len(m-1); // row index size
System.out.printf("%"+ris+"s ", " ");
for(int j=0; j<n; ++j)
System.out.printf("%" + colw[j] +"d ", j);
System.out.println();
System.out.printf("%"+ris+"s+"," ");
for(int j=0; j<totalWidth+n-1; ++j)
System.out.printf("-");
System.out.println();
while (rowStart >= rowEnd && colStart <= colEnd) {
// Print leftmost column from bottom to top
if (colStart <= colEnd) {
for (int i = rowStart; i >= rowEnd; i--) {
tab[i][colStart] = num++;
}
colStart++;
}
// Print top row from right to left
if (rowStart >= rowEnd) {
for (int i = colStart; i <= colEnd; i++) {
tab[rowEnd][i] = num++;
}
rowEnd++;
}
// Print rightmost column from top to bottom
if (colStart <= colEnd) {
for (int i = rowEnd; i <= rowStart; i++) {
tab[i][colEnd] = num++;
}
colEnd--;
}
// Print bottom row from left to right
if (rowStart >= rowEnd) {
for (int i = colEnd; i >= colStart; i--) {
tab[rowStart][i] = num++;
}
rowStart--;
}
}
// Prints the matrix
for(int i=0; i<m; ++i) {
System.out.printf("%"+ris+"d|", i);
for(int j=0; j<n; ++j)
System.out.printf("%" + colw[j] +"d ", tab[i][j]);
System.out.println();
}
System.out.println();
}
}

Finding the location of a number in a 2d array

I am trying to create a program that lets you find how many times a curtain number occurs in a 2d array. One of the things that I am required to do is to create a method called countInstence which counts the amount of times a number occurs but also where they are located in the array. the problem i'm having is how do I output the location of the the number
public int[][] createArray(int rSize, int cSize) {
Random rnd = new Random();
int[][] array = new int[rSize][cSize];
for (int row = 0; row < array.length; row++) {
for (int col = 0; col < array[0].length; col++) {
array[row][col] = rnd.nextInt(26);
}
}
return array;
}
public void print2dArray(int[][] array) {
for (int row = 0; row < array.length; row++) {
for (int col = 0; col < array[0].length; col++) {
System.out.print(array[row][col] + "\t");
}
System.out.println("\n");
}
}
public int countInstence(int[][] array, int search) {
int count = 0;
for (int row = 0; row < array.length; row++) {
for (int col = 0; col < array[0].length; col++) {
if (array[row][col] == search)
count++;
}
}
return count;
}
public static void main(String[] args) {
Journal5b call = new Journal5b();
Scanner in = new Scanner(System.in);
int[][] myArray;
int value;
myArray = call.createArray(10, 10);
call.print2dArray(myArray);
System.out.println("Enter a number to search for: ");
value = in.nextInt();
System.out.println("Your number occurred "
+ call.countInstence(myArray, value) + " Times");
}

Just insert a one line print statement inside of the if-statement and format to print the row and column of the current index, as below...
public int countInstance(int[][] array, int search) {
int count = 0;
for (int row = 0; row < array.length; row++) {
for (int col = 0; col < array[0].length; col++) {
if (array[row][col] == search) {
System.out.printf("Instance found at [%d, %d]\n", row, col);
count++;
}
}
}
return count;
}
If you aren't familiar with the System.out.printf call or the %d symbols, you can read more about it here.

Just add this line to the for loop
for (int row = 0; row < array.length; row++) {
for (int col = 0; col < array[0].length; col++) {
if (array[row][col] == search) {
System.out.printf("Instance found at [%d, %d]\n", row, col);// add this line
count++;
}
}
}

If you want to also use location at other place then just declare a List and add location to that list while searching for element.
public static List<String> location=new ArrayList<String>();
public int countInstence(int[][] array, int search) {
int count = 0;
for (int row = 0; row < array.length; row++) {
for (int col = 0; col < array[0].length; col++) {
if (array[row][col] == search)
{
count++;
String loc=row+","+col;
location.add(loc);
}
}
}
return count;
}
public static void main(String[] args) {
Test call = new Test();
Scanner in = new Scanner(System.in);
int[][] myArray;
int value;
myArray = call.createArray(10, 10);
call.print2dArray(myArray);
System.out.println("Enter a number to search for: ");
value = in.nextInt();
System.out.println("Your number occurred "
+ call.countInstence(myArray, value) + " Times");
System.out.println("locations :");
for(int i = 0; i < location.size(); i++) {
System.out.println(location.get(i));
}
}

I suggest using Points:
List<Point> locations=new ArrayList<Point>();
....
if (array[row][col] == search)
{
count++;
locations.add(new Point(row,col));
}

java performing array calculation [closed]

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The code below will print two square matrices and I need them to perform multiplication between the two matrices but i cant seem to get that part working. I put a comment right before that block of code where the problem is. But for now all it prints is zeros. Iv been looking online at a lot of sites but cant seem to get mine to work.
import java.util.*;
import java.math.*;
public class Main {
public static void main(String[] args) {
//create the grid
final int rowWidth = 9;
final int colHeight = 9;
Random rand = new Random();
int [][] board = new int [rowWidth][colHeight];
//fill the grid
for (int row = 0; row < board.length; row++) {
for (int col = 0; col < board[row].length; col++) {
board[row][col] = rand.nextInt(10);
}
}
//display output
for(int i = 0; i < board.length; i++) {
for(int j = 0; j < board[i].length; j++) {
System.out.print(board[i][j] + " ");
//System.out.println();
}
System.out.println();
}
System.out.println();
int [][] board2 = new int [rowWidth][colHeight];
//fill the grid
for (int row2 = 0; row2 < board2.length; row2++) {
for (int col2 = 0; col2 < board[row2].length; col2++) {
board[row2][col2] = rand.nextInt(10);
}
}
//display output
for(int m = 0; m < board2.length; m++) {
for(int n = 0; n < board[m].length; n++) {
System.out.print(board[m][n] + " ");
}
System.out.println();
}
//error is somewhere here
int[][] calculationMultiplication = new int[rowWidth][colHeight];
for (int l = 0; l < rowWidth; l++) {
for (int t = 0; t < colHeight; t++) {
for (int z = 0; z < rowWidth; z++) {
calculationMultiplication[l][t] = calculationMultiplication[l][t] + board[l][z] * board2[z][t];
}
}
}
//display output
System.out.println("\nProduct of the 2 matrices is ");
for (int i = 0; i < calculationMultiplication.length; i++) {
for (int j = 0; j < calculationMultiplication[0].length; j++) {
System.out.print(calculationMultiplication[i][j] + " ");
}
System.out.println();
}
} //end of main
} //end of class Main

The problem is that you've not filled the board2 array, so all its elements will be 0. In the for loop, you should also assign random values to board2. You are doing it twice for the board array.
//fill the grid
for (int row2 = 0; row2 < board2.length; row2++) {
for (int col2 = 0; col2 < board2[row2].length; col2++) { // notice 'board2[row].length'
board2[row2][col2] = rand.nextInt(10);
}
}
You should do something similar in the for loops where you display the array:
//display output
for (int m = 0; m < board2.length; m++) {
for (int n = 0; n < board2[m].length; n++) { // notice 'board2[row].length'
System.out.print(board2[m][n] + " ");
}
System.out.println();
}

board2 is always zero.
You fill the wrong array here:
//fill the grid
for (int row2 = 0; row2 < board2.length; row2++) {
for (int col2 = 0; col2 < board[row2].length; col2++) {
board[row2][col2] = rand.nextInt(10);
}
}

Basically you just did simple copy paste mistakes that can be avoidable if you used methods. I'll tell you how but first here's how you can discover your mistake:
System.out.println(String.format("%d * %d = %d",board[l][z], board2[z][t], board[l][z] * board2[z][t]));
Add this just before doing the calculation for calculationMultiplication[l][t]. Try if you want...
Anyway getting back to your mistakes, you have populated your first matrix only, the second one contain zeros (verify your code in the for loop for inserting random numbers into the second matrix), therefore any number multiplied by zero is equal to zero.
I haven't looked at all your code, because it contain a lot of copy paste which confused you and could confuse any one as well, so here's a better way to avoid mistakes in printing the matrix and inserting random numbers:
Printing:
void printMatrix(int[][] matrix){
for(int row =0; row < numOfRows; row++){
for(int col =0; col < numOfCols; col++){
System.out.print(matrix[row][col]+" ");
}
System.out.println(); // new line
}
}
Inserting:
void insertMatrix(int[][] matrix){
for(int row =0; row < numOfRows; row++){
for(int col =0; col < numOfCols; col++){
matrix[row][col] = rand.nextInt(10); // rand must be declared outside any method
}
}
}
Putting all together:
import java.util.*;
public class Main {
// create the grid
final static int rowWidth = 9;
final static int colHeight = 9;
static Random rand;
public static void main(String[] args) {
rand = new Random();
int[][] board = new int[rowWidth][colHeight];
int[][] board2 = new int[rowWidth][colHeight];
int[][] calculationMultiplication = new int[rowWidth][colHeight];
// fill
insertMatrxi(board);
// display output
printMatrix(board);
System.out.println();
// fill
insertMatrxi(board2);
// display output
printMatrix(board2);
for (int l = 0; l < rowWidth; l++) {
for (int t = 0; t < colHeight; t++) {
for (int z = 0; z < rowWidth; z++) {
calculationMultiplication[l][t] += board[l][z] * board2[z][t];
}
}
}
// display output
System.out.println("\nProduct of the 2 matrices is ");
printMatrix(calculationMultiplication);
} // end of main
public static void printMatrix(int[][] matrix) {
for (int row = 0; row < rowWidth; row++) {
for (int col = 0; col < colHeight; col++) {
System.out.print(matrix[row][col] + " ");
}
System.out.println(); // new line
}
}
public static void insertMatrxi(int[][] matrix) {
for (int row = 0; row < rowWidth; row++) {
for (int col = 0; col < colHeight; col++) {
matrix[row][col] = rand.nextInt(10);
}
}
}
} // end of class Main

Reverse the rows of a 2d array

Yesterday I asked a very similar question and I kind of messed up with asking it.
I need to pass an array to a method and inside of that method I need to swap the rows around so if it's
1 2 3
3 2 1
2 1 3
it needs to be
3 2 1
1 2 3
3 1 2
With the code I have right now it swaps the last column to the first column spot correctly then it puts the column that's supposed to be last.
3 1 2
1 3 2
3 2 1
Also, it needs to stay a void because I need to be modifying the original array so I can't set it as a temp array but I can use a temp integer to store.
Here is the code I have right now that's sort of working
public static void reverseRows(int[][] inTwoDArray)
{
for (int row = 0; row < inTwoDArray.length; row++)
{
for (int col = 0; col < inTwoDArray[row].length; col++)
{
int tempHolder = inTwoDArray[row][col];
inTwoDArray[row][col] = inTwoDArray[row][inTwoDArray[0].length - 1];
inTwoDArray[row][inTwoDArray[0].length - 1] = tempHolder;
}
}
}
any help would be great, I'm running out of hair to pull out! Thanks!

First, how to reverse a single 1-D array:
for(int i = 0; i < array.length / 2; i++) {
int temp = array[i];
array[i] = array[array.length - i - 1];
array[array.length - i - 1] = temp;
}
Note that you must stop in half of your array or you would swap it twice (it would be the same one you started with).
Then put it in another for loop:
for(int j = 0; j < array.length; j++){
for(int i = 0; i < array[j].length / 2; i++) {
int temp = array[j][i];
array[j][i] = array[j][array[j].length - i - 1];
array[j][array[j].length - i - 1] = temp;
}
}
Another approach would be to use some library method such as from ArrayUtils#reverse():
ArrayUtils.reverse(array);
And then again put into a cycle:
for(int i = 0; i < array.length; i++){
ArrayUtils.reverse(array[i]);
}

I guess this the easiest approach, tried and tested
For instance, you have
1 2
3 4
and you want
2 1
4 3
You can reverse the loop, without any extra space or inbuilt function.
Solution:
for(int i =0;i<arr.length;i++) //arr.length=no of rows
{
for(int j = arr[i].length-1;j>=0;j--)//arr[i].length=no of col in a ith row
{
System.out.print(arr[i][j]+" ");
}
System.out.println();
}

Not sure if I didn't confuse what array stores the rows and which one the columns.... but this should work (long time since I've done Java last, so be nice to me when spotting any errors please ^^):
public static void reverseRows(int[][] array)
{
for (int i = 0 ; i < array.length ; i++) { // for each row...
int[] reversed = new int[array[i].length]; // ... create a temporary array that will hold the reversed inner one ...
for(int j = 0 ; j < array[i].length ; j++) { // ... and for each column ...
reversed[reversed.length - 1 - j] = array[i][j]; // ... insert the current element at the mirrored position of our temporary array
}
array[i] = reversed; // finally use the reversed array as new row.
}
}

Java Code :-
import java.util.Scanner;
public class Rev_Two_D {
static int col;
static int row;
static int[][] trans_arr = new int[col][row];
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner sc = new Scanner(System.in);
int m = sc.nextInt();
row = m;
int n = sc.nextInt();
col = n;
int[][] arr = new int[row][col];
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
arr[i][j] = sc.nextInt();
System.out.print(arr[i][j] + " ");
}
System.out.println();
}
for (int j = 0; j < arr.length; j++) {
for (int i = 0; i < arr[j].length / 2; i++) {
int temp = arr[j][i];
arr[j][i] = arr[j][arr[j].length - i - 1];
arr[j][arr[j].length - i - 1] = temp;
}
}
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
System.out.print(arr[i][j] + " ");
}
System.out.println();
}
}
}

Reverse of two D array - Print your two D array in reverse order
public void reverse(){
int row = 3;
int col = 3;
int[][] arr = new int[row][col];
int k=0;
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++,k++) {
arr[i][j] = k;
System.out.print(arr[i][j] + " ");
}
System.out.println();
}
System.out.println();
for (int i = arr.length -1; i >=0 ; i--) {
for (int j = arr.length -1; j >=0 ; j--) {
System.out.print(arr[i][j] + " ");
}
System.out.println();
}
}

public static void main(String[] args) {
int [][] a={{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};
for(int i=0 ; i<a.length;i++)
{
for(int j=0 ; j<a.length;j++)
{
System.out.print(a[i][j]+",");
}
System.out.println();
}
System.out.println("***************************");
for(int i=0 ; i<a.length;i++)
{
for(int j=a.length-1 ; j>=0;j--)
{
System.out.print(a[i][j]+",");
}
System.out.println();
}
}

Reverse 2 D Array
public static void main(String[] args) {
int a[][] = {{1,2,3},
{4,5,6},
{8,9,10,12,15}
};
for(int i=0 ; i<a.length;i++)
{
for(int j=0 ; j<a[i].length;j++)
{
System.out.print(a[i][j]+",");
}
System.out.println();
}
for(int i=0 ; i<a.length;i++)
{
for(int j=a[i].length-1 ; j>=0;j--)
{
System.out.print(a[i][j]+",");
}
System.out.println();
}

Converting one dimesion array into 2 dimensions array of 9 columns

The following code is supposed to take a String array of one element ,splits it into
nine elements those nine elements should be store into another array of two dimensions .
each element of them should be store in a column alone.
But when I print the elements of the two dimensional array the last element only is printed
Why?
public class StringFragementation {
public static String[][] mymethod(String[] mystring) {
String[][] india = new String[1][9];
String mystringno2[];
mystringno2 = mystring;
int i = 0;
int j = 0;
String x = "_";
int i1;
do {
i = mystringno2[j].indexOf(x, i);
i1 = i + 1;
i1 = mystringno2[j].indexOf(x, i1);
if (i1 <= -1) {
break;
}
i++;
int row, col = 0;
for (row = 0; row < 1; row++) {
for (col = 0; col < 9; col++) {
india[row][col] = mystringno2[j].substring(i, i1);
}
}
}
while (j < mystringno2.length);
return india;
}
public static void main(String[] args) {
String[][] singapore = new String[1][9];
String[] s = {"_Netherlands_Iceland_Norway_Denmark_Usa_Brazil_Argentina_Colombuia_Bolivia_"};
singapore = mymethod(s);
for (int row = 0; row < 1; row++)
for (int col = 0; col < 9; col++) {
System.out.print(singapore[0][0] + "\t");
}
}
}

the problem is here :
for( row=0;row<1;row++){
for( col=0;col< 9;col++) {
india[row][col] = mystringno2[j].substring(i, i1);
}
}
you fill the 9 column by the same word because the i and i1 never change through this loop , then restart the array and fill with Netherlands then Iceland_Norway_Denmark until the last word
Bolivia , so your array fill with Bolivia in 9 columns
the correct way is :
int row = 0, col = 0;
String[][] india = new String[1][9];
String mystringno2[];
mystringno2 = mystring;
int i = 0;
int j = 0;
String x = "_";
int i1;
do {
i = mystringno2[j].indexOf(x, i);
i1 = i + 1;
i1 = mystringno2[j].indexOf(x, i1);
if (i1 <= -1) {
break;
}
i++;
india[0][col] = mystringno2[j].substring(i, i1);
System.out.println("dfref " + row + " " + col + " " + india[row][col]);
col++;
} while (j < mystringno2.length);
return india;
and in the main :
for (int row = 0; row < 1; row++) {
for (int col = 0; col < 9; col++) {
System.out.print(singapore[row][col] + "\t");
}
}
there are a smallest way to do this split , look at this code :
class StringFragementation {
public static String[] mymethod(String mystring) {
String[] split = mystring.split("_");
return split;
}
public static void main(String[] args) {
String[] singapore = new String[9];
String s = "Netherlands_Iceland_Norway_Denmark_Usa_Brazil_Argentina_Colombuia_Bolivia_";
singapore = mymethod(s);
for (int col = 0; col < 9; col++) {
System.out.println(singapore[col]);
}
}
}