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How to print a 2D array in java

Hello so am trying to create a 2D array of int with random number of rows and columns and a random starting and ending points using java to apply the A* algorithm on it.
When i add {S} and {E} to define the tow points and print it there are numbers outside of the 2D array printed.
`Random rand = new Random();
int min = 2, max = 10;
// a random number of rows and columns
int a = (int)(Math.random() * (max - min + 1)) + min;
// the location of the starting point.
int row_start = rand.nextInt(a);
int col_start = rand.nextInt(a);
// the location of the ending point.
int row_end = rand.nextInt(a);
int col_end = rand.nextInt(a);
int [][] M = new int [a][a];
public void create() {
//empty: 0; grass: 1; sand: 2; water: 3; wall: 4.
for (int i = 0; i < a; i++) {
for (int j = 0; j < a; j++) {
M[i][j] = rand.nextInt(5);
}
}
for (int i = 0; i < a; i++) {
for (int j = 0; j < a; j++) {
System.out.print(" " +M[i][j] + "\t");
if(row_start == i && col_start == j) {
System.out.print("{S}" + "\t");
}
if(row_end == i && col_end == j) {
System.out.print("{E}" + "\t");
}
}
System.out.print("\n");
}
}`
the output looks like this:
1 0 4 0
2 {S} 1 2 2
4 4 {E} 0 3
2 0 3 3
the 2 and 3 shouldn't appear there.

The problem is that you always print m[i][j].
What you need is to only print m[i][j] when i and j are not S and E positions. When i and j are S and E positions, print S or E. Otherwise, print m[i][j].
if(row_start == i && col_start == j) {
System.out.print("{S}" + "\t");
} else if(row_end == i && col_end == j) {
System.out.print("{E}" + "\t");
} else {
System.out.print(" " +M[i][j] + "\t");
}

How can I test credit numbers with hyphens (" -" ) to get it as INVALID . When I tried 4003-6000-0000-0014 i am getting errors

I cant get credit card numbers containing hymens as INVALID such as 4003-6000-0000-0014 must give me INVALID but its giving me errors of string.
public class prog {
public static void main(String[] args)
{
Scanner userInput = new Scanner(System.in) ;
System.out.println("How many credit card you want to check?");
int numOfCredit = userInput.nextInt() ;
int creditnumbers[] = new int[numOfCredit] ;
for (int i = 0 ; i<numOfCredit ; i++)
{
System.out.println("Enter credit card number "+(i+1)+": ") ;
String creditNumber = userInput.next() ;
validateCreditCardNumber(creditNumber);
}
}
private static void validateCreditCardNumber(String str) { // function to check credit numbers
int[] ints = new int[str.length()];
for (int i = 0; i < str.length(); i++) {
ints[i] = Integer.parseInt(str.substring(i, i + 1));
}
for (int i = ints.length - 2; i >= 0; i = i - 2) {
int j = ints[i];
j = j * 2;
if (j > 9) {
j = j % 10 + 1;
}
ints[i] = j;
}
int sum = 0;
for (int i = 0; i < ints.length; i++)
{
sum += ints[i];
}
if (sum % 10 == 0)
{
System.out.println("VALID");
}
else
{
System.out.println("INVALID");
}
}
}
I get these errors after running with hymens :
Exception in thread "main" java.lang.NumberFormatException: For input string: "-"
at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:68)
at java.base/java.lang.Integer.parseInt(Integer.java:642)
at java.base/java.lang.Integer.parseInt(Integer.java:770)
at testing/testing.prog.validateCreditCardNumber(prog.java:33)
at testing/testing.prog.main(prog.java:22)

you can replace in your string "-" with "" (blank) and then apply this function:
String card = "4003-6000-0000-0014";
Boolean t = check(card.replace("-",""));
public static boolean check(String ccNumber)
{
int sum = 0;
boolean alternate = false;
for (int i = ccNumber.length() - 1; i >= 0; i--)
{
int n = Integer.parseInt(ccNumber.substring(i, i + 1));
if (alternate)
{
n *= 2;
if (n > 9)
{
n = (n % 10) + 1;
}
}
sum += n;
alternate = !alternate;
}
return (sum % 10 == 0);
}

Array count logic error

Made some edits to the code to try and figure out why my X's [-1] are not being included in finding my average for that row. That is throwing of my averages. Any idea why It is not counting my -1's?
output[expected]:
USER INPUT: 3
O O O
X X X
X X X
TOTAL OPENNESS OF [I][J] = 1
TOTAL OPENNESS OF [I][J+1] = 2
TOTAL OPENNESS OF [I][J+2] = 1
TOTAL SUM AVERAGE FOR THAT ROW = 1.3
HOWEVER..FOR ROW 2 AND ROW 3
TOTAL SUM AVERAGE FOR THOSE ROWS = 0
WHICH IS INCORRECT IT SHOULD = -1
public static void openfactor(char[][] mazeValue, int n){
for(int i = 1; i<=n; i++)
{
double rowAvg=0;
double totalRowAvg=0;
for(int j=1;j<=n;j++)
{
int count=0;
int totalOpeness=0;
int totalRowOpeness = 0;
//double rowAvg=0;
if(mazeValue[i][j]=='X'){
System.out.println("tHIS IS AN X FOR : [" + i + "]" +"[" + j + "] IS -1 ");
count = -1;
}
else
{
//YOU NEED TO VERIFY THAT J IS NOT OUT OF BOUND
if( j-1>=1)
{
if(mazeValue[i][j-1]=='O')
count++;
}
// System.out.println("cout: "+count);
if(i-1>=1 && j-1>=1)
{
if(mazeValue[i-1][j-1]=='O')
count++;
}
// System.out.println("cout: "+count);
if(i-1>=1)
{
if(mazeValue[i-1][j]=='O')
count++;
}
// System.out.println("cout: "+count);
if(j+1<=n)
{
if(mazeValue[i][j+1]=='O')
count++;
}
// System.out.println("cout: "+count);
if(j+1<=n && i+1<=n)
{
if(mazeValue[i+1][j+1]=='O')
count++;
}
if (i+1<=n)
{
if(mazeValue[i+1][j]=='O')
count++;
}
// System.out.println("cout: "+count);
if(j-1>=1 && i+1<=n)
{
if(mazeValue[i+1][j-1]=='O')
count++;
}
if(i-1>=1 && j+1<=n)
{
if(mazeValue[i-1][j+1]=='O')
count++;
}
// System.out.println("cout: "+count);
totalOpeness = totalOpeness +count;
System.out.println("TOTAL OPENESS FOR : [" + i + "]" +"[" + j + "] IS " +totalOpeness);
totalRowOpeness = totalRowOpeness + totalOpeness;
//}//eND OF iF CONDITION\
}
rowAvg = (double)totalRowOpeness/(double)n;
System.out.println("ROW AVERAGE: "+rowAvg);
totalRowAvg = totalRowAvg + rowAvg;
System.out.println("SUM ROW AVERAGE: "+totalRowAvg);
}
System.out.println("TOTAL SUM ROW AVERAGE: " +totalRowAvg);
}
}
public static void printMaze(char mazeValue[][]) {
System.out.println("MAZE");
for (int i = 1; i < mazeValue.length; i++) {
for (int j = 1; j < mazeValue[i].length; j++) {
System.out.printf("%5c", mazeValue[i][j]);
}
System.out.printf("\n");
}
}
public static void main(String[] args) {
// TODO code application logic here
Scanner kbd = new Scanner(System.in);
System.out.println("ENTER A SINGLE INTEGER: ");
int n = kbd.nextInt();
char[][] mazeValue = new char[n + 1][n + 1];
System.out.println("ENTER A PATH: ");
for (int i = 0; i < mazeValue.length; i++) {
for (int j = 0; j < mazeValue[i].length; j++) {
if (i == 0 || j == 0 || i == n + 1 || j == n + 1)
mazeValue[i][j] = 'X';
else {
mazeValue[i][j] = kbd.next().charAt(0);
}
}
}
printMaze(mazeValue);
horizontalPath(mazeValue, n);
System.out.println(" ");
verticalPath(mazeValue,n);
System.out.println(" ");
openfactor(mazeValue, n);
}
}

I do not completely understand what u want to accomplished but I am going to to assume you want to find repeated values, do this using some search algorithm below is an example of a binary search. Hope it helps.
import java.util.Scanner;
class BinarySearch
{
public static void main(String args[])
{
int c, first, last, middle, n, search, array[];
Scanner in = new Scanner(System.in);
System.out.println("Enter number of elements");
n = in.nextInt();
array = new int[n];
System.out.println("Enter " + n + " integers");
for (c = 0; c < n; c++)
array[c] = in.nextInt();
System.out.println("Enter value to find");
search = in.nextInt();
first = 0;
last = n - 1;
middle = (first + last)/2;
while( first <= last )
{
if ( array[middle] < search )
first = middle + 1;
else if ( array[middle] == search )
{
System.out.println(search + " found at location " + (middle + 1) + ".");
break;
}
else
last = middle - 1;
middle = (first + last)/2;
}
if ( first > last )
System.out.println(search + " is not present in the list.\n");
}
}

Here's the complete code for your request. you need to reorder your if statements a little bit your logic was right:
and here is the output :
MAZE
O O X
O O O
X X O
TOTAL OPENESS FOR : [0][0] IS 3
TOTAL OPENESS FOR : [0][1] IS 4
THERE IS AN X HERE FOR : [0][2]
Average of O's in this row is : 66.66667%
TOTAL OPENESS FOR : [1][0] IS 3
TOTAL OPENESS FOR : [1][1] IS 5
TOTAL OPENESS FOR : [1][2] IS 3
Average of O's in this row is : 100.0%
THERE IS AN X HERE FOR : [2][0]
THERE IS AN X HERE FOR : [2][1]
TOTAL OPENESS FOR : [2][2] IS 2
Average of O's in this row is : 33.333336%
here's the code:
import java.util.Scanner;
public class sof {
public static boolean IsOutOfBound(int i, int j, int n)
{
if (i-1<1 || j-1<1 || i+1>n || j+1>n)
return true;
else
return false;
}
public static void openfactor(char[][] mazeValue, int n)
{
for(int i = 0; i<n; i++)
{
int TotalCounts=0;
for(int j=0;j<n;j++)
{
int count=0;
if(mazeValue[i][j]=='X'){
System.out.println("THERE IS AN X HERE FOR : [" + i + "]" +"[" + j + "] ");
//TotalCounts--;
}
else
{
//YOU NEED TO VERIFY THAT J IS NOT OUT OF BOUND
if( j-1>=0)
{
if(mazeValue[i][j-1]=='O')
count++;
}
// System.out.println("cout: "+count);
if(i-1>=0 && j-1>=0)
{
if(mazeValue[i-1][j-1]=='O')
count++;
}
// System.out.println("cout: "+count);
if(i-1>=0)
{
if(mazeValue[i-1][j]=='O')
count++;
}
// System.out.println("cout: "+count);
if(j+1<n)
{
if(mazeValue[i][j+1]=='O')
count++;
}
// System.out.println("cout: "+count);
if(j+1<n && i+1<n)
{
if(mazeValue[i+1][j+1]=='O')
count++;
}
if (i+1<n)
{
if(mazeValue[i+1][j]=='O')
count++;
}
// System.out.println("cout: "+count);
if(j-1>=0 && i+1<n)
{
if(mazeValue[i+1][j-1]=='O')
count++;
}
if(i-1>=0 && j+1<n)
{
if(mazeValue[j+1][i-1]=='O')
count++;
}
// System.out.println("cout: "+count);
//totalOpeness = totalOpeness +count;
System.out.println("TOTAL OPENESS FOR : [" + i + "]" +"[" + j + "] IS " + count);
TotalCounts++;
}//END OF else CONDITION
}//End of J loop
float Average = ((float)TotalCounts/(float)n) * 100;
System.out.println("Average of O's in this row is : " + Average+ "%");
}//End of I loop
}
public static void printMaze(char mazeValue[][],int n) {
System.out.println("MAZE");
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
System.out.printf("%5c", mazeValue[i][j]);
}
System.out.printf("\n");
}
}
public static void main(String[] args) {
// TODO code application logic here
// TODO code application logic here
Scanner kbd = new Scanner(System.in);
System.out.println("ENTER A SINGLE INTEGER: ");
int n = kbd.nextInt();
char[][] mazeValue = new char[n][n];
System.out.println("ENTER A PATH: ");
for (int i = 0; i <n; i++) {
for (int j = 0; j < n; j++) {
//if (i == 0 || j == 0 || i == n + 1 || j == n + 1)
// mazeValue[i][j] = 'X';
// else {
mazeValue[i][j] = kbd.next().charAt(0);
// }
}
}
printMaze(mazeValue,n);
openfactor(mazeValue, n);
}
}

Making a hollow diamond with a word in it

What I need is a little modification to my code so that every part of my hollow diamond prints a letter of the word "HURRICANE"
My code is:
String st1 = "HURRICANE";
int a = 0;
for (int i = 5; i >= 1; i--) {
for (int j = 1; j <= 9; j++) {
if (j == i || (10 - i) == j) {
System.out.print(st1.charAt(a)); //needs change
} else {
System.out.print(' ');
}
}
System.out.println();
}
for (int i = 2; i <= 5; i++) {
for (int j = 1; j <= 9; j++) {
if (j == i || (10 - i) == j) {
System.out.print(st1.charAt(a)); //needs change
} else {
System.out.print(' ');
}
}
System.out.println();
}
The output comes out as:
H
H H
H H
H H
H H
H H
H H
H H
H
I need to modify my "charAt" statement a little so it comes out to be:
H
U U
R R
R R
I I
C C
A A
N N
E
How should I make my print statement?

It's worth noting that the example provided only works for Strings the same length as "HURRICANE". A superior solution would work for all strings.
Partial solution for you to complete, since I guess it's your coursework and I don't want you to copy / paste / fail exams :P
public static void main(String[] args) {
String st1 = "HURRICANE";
char[] st1CharArray = st1.toCharArray();
int maxSpaces = st1CharArray.length / 2 + 1;
for (int i = 0; i <= st1CharArray.length / 2; i++) {
if (i == 0) {
System.out.println(getSpacesString(maxSpaces) + st1CharArray[i]);
} else {
System.out.println(getSpacesString(maxSpaces - i)
+ st1CharArray[i] + getSpacesString(i * 2 - 1)
+ st1CharArray[i]);
}
}
// Loop from st1CharArray.length / 2 + 1 and get the second half done.
}
private static String getSpacesString(int numberOfSpaces) {
StringBuilder strBuilder = new StringBuilder();
for (int i = 0; i < numberOfSpaces; i++) {
strBuilder.append(" ");
}
return strBuilder.toString();
}

//: Playground - noun: a place where people can play
import UIKit
var name : String = "HURRICANE"
var dimensions : Int = name.count - 1
var k : Int = 0
for rows in 0...dimensions{
for columns in 0...dimensions{
k = abs( (dimensions/2) - rows )
if columns == k || columns == dimensions - k{
print(Array(name)[rows], terminator: "")
}
else{
print(" ", terminator: "" )
}
}
print("")
}

String st1 = "HURRICANE";
int a = 0;
for (int i = 5; i >= 1; i--) {
for (int j = 1; j <= 9; j++) {
if (j == i || (10 - i) == j) {
System.out.print(st1.charAt(5 - i));
} else {
System.out.print(' ');
}
}
System.out.println();
}
for (int i = 2; i <= 5; i++) {
for (int j = 1; j <= 9; j++) {
if (j == i || (10 - i) == j) {
System.out.print(st1.charAt(3 + i));
} else {
System.out.print(' ');
}
}
System.out.println();
}

Let's assume that a word has an odd number of characters, otherwise we get a crooked diamond.
Try it online!
public static void main(String[] args) {
String str = "abrahadabra";
int n = str.length() / 2;
for (int i = -n, ch = 0; i <= n && ch < str.length(); i++, ch++) {
for (int j = -n; j <= n; j++)
if (Math.abs(i) + Math.abs(j) == n)
System.out.print(str.charAt(ch));
else
System.out.print(" ");
System.out.println();
}
}
Output:
a
b b
r r
a a
h h
a a
d d
a a
b b
r r
a

How to replace an integer element in a 2d array with a string type, using a Random

I have this table (2d array) and I'm using a Random utility from numbers 0-4 to select a row and column to replace a number with the letter "P" and I have everything but I get this.
- Type mismatch: cannot convert from String
to int
- Type mismatch: cannot convert from
Random to int
- Type mismatch: cannot convert from
Random to int
Meanwhile this question How to change value of array element in 2D arrays? says you can just do
someArray[row][column] = "x";
Here is what I have (I assume my problem is with using the random)
import java.util.Random;
public class Server{
private int number;
private boolean pennyLanded;
public Server()
{
int n = 0;
number = n;
pennyLanded = false;
}
public boolean pennyLanded()
{
return pennyLanded;
}
public void setPennyLanded()
{
pennyLanded = true;
}
public int getNumber()
{
return number;
}
public String toString()
{
if (pennyLanded)
return "P";
else
return "" + number;
}
public static int[][] tableMaker(){
int[][] table = new int[5][5];
for(int i=0; i<table.length; i++){
for(int j=0; j<table.length; j++){
if(i==2 && j==2){
table[i][j] =3;
}
else if(i==0 || i==4){
table[i][j] = 1;
}
else if(j==4 || j==0){
table[i][j] = 1;
}
else if((i==1 || i==3) && (j>0 || j<4)){
table[i][j] = 2;
}
else if((i==2 && j==1) || (i==2 && j==3)){
table[i][j] = 2;
}
}
}
for(int i=0; i<table.length; i++){
for(int j=0; j<table.length; j++){
System.out.print(table[i][j] + " ");
}
System.out.println();
}
return table;
}
public static int[][] tossPenny(){
Random row = new Random();
Random column = new Random();
int[][] table = Server.tableMaker();
for(int i=0; i<5; i++){
table[row.nextInt(4)][column.nextInt(4)] = -1;
}
return table;
}
}
The table is printed in a Client class
public class Client{
public static void main(String[] args){
System.out.println(Server.tableMaker());
}
}
I Don't know how simple of a fix this is, and I have searched I just have a particular problem
The table is printed as so
1 1 1 1 1
1 2 2 2 1
1 2 3 2 1
1 2 2 2 1
1 1 1 1 1
And I would like something like this say the random puts out 1 and 2
1 1 1 1 1
1 2 P 2 1
1 2 3 2 1
1 2 2 2 1
1 1 1 1 1

You have to use row.nextInt(int max) instead of row, where the generated random integer n is 0 <= n < max. The parameter of new Random() only defines a seed, so I suggest you not use a constant number there unless you want your random algorithm to be deterministic.
Furthermore you mixes up the types a bit. tableMaker() should be String[][] in order to write Strings into it and tossPenny() should be void since it doesn't return anything.
import java.util.Random;
public class Server {
public static String[][] tableMaker() {
String[][] table = new String[5][5];
for (int i = 0; i < table.length; i++) {
for (int j = 0; j < table.length; j++) {
if (i == 2 && j == 2) {
table[i][j] = "" + 3; // Converting int 3 to String "3"
} else if (i == 0 || i == 4) {
table[i][j] = "" + 1;
} else if (j == 4 || j == 0) {
table[i][j] = "" + 1;
} else if ((i == 1 || i == 3) && (j > 0 || j < 4)) {
table[i][j] = "" + 2;
} else if ((i == 2 && j == 1) || (i == 2 && j == 3)) {
table[i][j] = "" + 2;
}
}
}
for (int i = 0; i < table.length; i++) {
for (int j = 0; j < table.length; j++) {
System.out.print(table[i][j] + " ");
}
System.out.println();
}
return table;
}
public static void tossPenny(int a) {
Random row = new Random();
Random column = new Random();
String Penny = "P";
String[][] table = Server.tableMaker();
for (int i = 0; i < 5; i++) {
table[row.nextInt(5)][column.nextInt(5)] = Penny;
}
}
}

Was able to figure it out with help of a IRL friend and this avoids the memory store errors as seen before, Server is below
import java.util.Random;
public class Server{
private static int[][] table;
public static int[][] tableMaker(){
table = new int[5][5];
for(int i=0; i<table.length; i++){
for(int j=0; j<table.length; j++){
if(i==2 && j==2){
table[i][j] =3;
}
else if(i==0 || i==4){
table[i][j] = 1;
}
else if(j==4 || j==0){
table[i][j] = 1;
}
else if((i==1 || i==3) && (j>0 || j<4)){
table[i][j] = 2;
}
else if((i==2 && j==1) || (i==2 && j==3)){
table[i][j] = 2;
}
}
}
return table;
}
public static void printTable(){
for(int i=0; i<table.length; i++){
for(int j=0; j<table.length; j++){
if(table[i][j] == -1) System.out.print("P ");
else System.out.print(table[i][j] + " ");
}
System.out.println();
}
}
public static int[][] tossPenny(){
Random row = new Random();
Random column = new Random();
for(int i=0; i<5; i++){
table[row.nextInt(4)][column.nextInt(4)] = -1;
}
return table;
}
}
Client is here
import java.util.Scanner;
public class Client{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
Server.tableMaker();
Server.printTable();
System.out.println();
Server.tossPenny();
Server.printTable();
input.close();
}
}
Thanks a lot everyone especially #DavidWallace You helped me get around most of my problems and I was able to fix everything using the private static int[][] table;