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How to print Two-Dimensional Array like table
(16 answers)
Closed 9 years ago.
I'd like to print an inputed 2-dimensional array like a table
i.e if for some reason they put in all 1s...
1 1 1 1
1 1 1 1
1 1 1 1
1 1 1 1
Just like so above but in the console on Java eclipse, no fancy buttons and GUI's but in the console, here is what I have....
import java.util.Scanner;
public class Client {
public static void main(String[] args){
Scanner input = new Scanner(System.in);
int[][] table = new int[4][4];
for (int i=0; i < table.length; i++) {
for (int j=0; j < table.length; j++) {
System.out.println("Enter a number.");
int x = input.nextInt();
table[i][j] = x;
System.out.print(table[i][j] + " ");
}
System.out.println();
}
System.out.println(table);
}
}
And this is what I get when I input everything and the console terminates:
Enter a number.
1
1 Enter a number.
1
1 Enter a number.
1
1 Enter a number.
1
1
[[I#3fa1732d
Consider using java.util.Arrays.
There is a method in there called deepToString. This will work great here.
System.out.println(Arrays.deepToString(table));
Relevant here: Simplest way to print an array in Java
You need to print out the array separately from entering the number. So you can do something like this:
public class PrintArray {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int[][] table = new int[4][4];
for (int i = 0; i < table.length; i++) {
for (int j = 0; j < table.length; j++) {
// System.out.println("Enter a number.");
int x = input.nextInt();
table[i][j] = x;
}
//System.out.println();
}
// System.out.println(table);
for (int i = 0; i < table.length; i++) {
for (int j = 0; j < table[i].length; j++) {
System.out.print(table[i][j] + " ");
}
System.out.println();
}
}
}
You'll have loop back through those arrays to print out the contents. an array's toString() just prints the reference value.
System.out.print(table) calls a method in array class that prints out the identifier of the vairable. you need to either create a for loop that will print out each element like System.out.print(table[i][j]) or use the Arrays class and say Arrays.toString(table);
Try copying this simple for loop to printing a 4x4 table:
Scanner input = new Scanner();
int numArray [] [] = new int [4] [4];
for ( int c = 0; c < 4; c++ ) {
for (int d = 0; d < 4; d++) {
System.out.print("Enter number : ");
nunArray [c][d] = input.nextInt();
}
}
for (int a = 1; a<5;a++) {
for (int b = 1; b <5;b++) {
System.out.print(numArray [a][b]+" ");
}
System.out.println();
}
Related
I just learned how to use nested loops today and the task I am required to do is quite simple but I am not able to execute it properly, although with the same idea.
The task is to input a character, an integer that is the rows**(n), and another integer that is the columns **(m)
It should display the rectangular pattern with n rows and m columns
Sample input:
*
3
2
Here the number of rows is 3 and the number of columns is 2
Sample output:
**
**
**
This has to be done using nested for loops only
My code:
import java.util.Scanner;
class Example {
public static void main (String[] args) {
Scanner keyboard = new Scanner(System.in);
String character = keyboard.next();
int n = keyboard.nextInt();
int m = keyboard.nextInt();
for (int x = m; x <= m; x++) {
for (int y =n ; y <= n; y++) {
System.out.print(character);
}
System.out.println("");
}
}
}
The output I am getting:
*
You should use a loop like this start from 0 to row and j from 0 to col for each row, and close the scanner after reading
public static void main(String[] arg) {
Scanner keyboard = new Scanner(System.in);
String character = keyboard.next();
int col = keyboard.nextInt();
int row = keyboard.nextInt();
for (int i = 0; i < row; i++) {
for (int j = 0; j < col; j++) {
System.out.print(character);
}
System.out.println("");
}
keyboard.close();
}
, output
***
***
You should start from 0 in both loops until reaching < m and < n as follows:
Scanner keyboard = new Scanner(System.in);
String character = keyboard.next();
int n = keyboard.nextInt();
int m = keyboard.nextInt();
for (int x = 0; x < m; x++){
for (int y = 0; y < n; y++){
System.out.print(character);
}
System.out.println("");
}
A sample input/output would be:
*
3
2
***
***
what is wrong in your code is that you are starting loop from m itself instead you should think it like how many times you want to run the loop.
With that in mind try running the code from 0 to m and inner loop from 0 to n.
This mindset will help you in learning while loop also.
import java.util.Scanner;
class Example {
public static void main (String[] args)
{
Scanner keyboard = new Scanner(System.in);
String character = keyboard.next();
int n = keyboard.nextInt();
int m = keyboard.nextInt();
for (int x = 0;x<m;x++){
for (int y=0;y<n;y++){
System.out.print(character);
}
System.out.println("");
}
}
}
I was trying to do a 2D array program to demonstrate a TRANSPOSE but I am getting error .. here is my code.
import java.util.Scanner;
/* To demonstrate TRANSPOSE USING 2-D array */
public class Array_2ddd {
public static void main(String args[]) {
Scanner s1 = new Scanner(System.in);
int i, j;
int myArray1[][] = new int[9][9];
int myArray2[][] = new int[9][9];
for (i = 0; i < 9; i++) {
for (j = 0; j < 9; j++) {
System.out.println("Enter array from 1 to 9");
myArray1[i][j] = s1.nextInt();
System.out.print("your array is" + myArray2[i][j]);
}
}
// Transposing now...
for (i = 0; i < 9; i++) {
for (j = 0; j < 9; j++) {
myArray2[i][j] = myArray1[j][i];
}
}
// After transposing
for (i = 0; i < 9; i++) {
for (j = 0; j < 9; j++) {
System.out.print("Your array is as follow" + myArray2[i][j]);
}
}
}
}
EDIT: My error during runtime (Solved)
EDIT 2: Solved
EDIT 3: The loop is in infinity ..it keeps on asking for values fromt the user even when i wrote i<9 and j<9..it still keeps on asking for values till infinity..
There are several errors in your code, also it is recommend that the dimensions of the array is to be declared as a final int, so your code works for all matrix sizes and that debugging is easier. In your original code, the errors are:
At the input step, you are printing one element of myArray[2] before you perform the transpose. That means, you are getting your array is0.
In the section commented "After transposing", you are outputting your array wrong. Namely, for each entry, you call System.out.print("Your array is as follow" + myArray2[i][j]);, and that you forgot to add a new line after each row (when inner loop is finished).
"..it keeps on asking for values fromt the user even when i wrote i<9 and j<9..it still keeps on asking for values till infinity.." There are 81 entries for the 9-by-9 case and you did not output which i,j index to be applied. You probably mistaken an infinite loop with a long but terminating loop.
Your transpose step is good.
Here is a refined version of your code which allows you to input array (in reading order, or more technically, row-major order), create a transposed array. You can copy and compare your current code with this code directly to test it.
public static void main(String args[]) {
final int m = 9; // Rows
final int n = 9; // Columns
Scanner s1 = new Scanner(System.in);
int i, j;
int myArray1[][] = new int[m][n]; // Original array, m rows n cols
int myArray2[][] = new int[n][m]; // Transposed array, n rows m cols
// Input
for (i = 0; i < m; i++) {
for (j = 0; j < n; j++) {
// Should be only prompt.
// Improved to show which entry will be affected.
System.out.printf("[%d][%d]" + "Enter array from 1 to 9\n", i, j);
myArray1[i][j] = s1.nextInt();
}
}
// Transposing now (watch for the ordering of m, n in loops)...
for (i = 0; i < n; i++)
{
for (j = 0; j < m; j++)
{
myArray2[i][j] = myArray1[j][i];
}
}
// After transposing, output
System.out.print("Your array is:\n");
for (i = 0; i < m; i++) {
for (j = 0; j < n; j++) {
System.out.print(myArray1[i][j] + " ");
}
System.out.println(); // New line after row is finished
}
System.out.print("Your transposed array is:\n");
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
System.out.print(myArray2[i][j] + " ");
}
System.out.println();
}
s1.close();
}
For an array with three rows (m = 3) and four columns (n = 4), I inputted the numbers from 0 to 9, and then 0, 1, 2. As expected, the output should be:
Your array is:
0 1 2 3
4 5 6 7
8 9 0 1
Your transposed array is:
0 4 8
1 5 9
2 6 0
3 7 1
You define your matrix as 9x9
int myArray1[][] = new int[9][9];
But actually you want to insert 10x10 items:
for (i = 0; i <= 9; i++)
{
for (j = 0; j <= 9; j++)
So either:
Redefine your arrays to store 10x10 items
int myArray1[][] = new int[10][10];
Only read and store 9x9 items in your defined array
for (i = 0; i < 9; i++) {
for (j = 0; j < 9; j++)
You haven't close your first outer for loop i.e in line 17 and change your array size to 10,as you wanted take 10 input (for 0 to 9 = 10 values).
I want to create a 2D array using the user's input and the creating random numbers in the second line.
E.g:
Output should be:
If the user enters "7" then:
1 2 3 4 5 6 7 (User's input)
0 2 4 8 9 8 5 (Random numbers)
but instead I only get one random number.
My code is working but I can't see to create the array correctly.
My code:
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter number of exits: ");
int n = input.nextInt();
int [][] A = new int[2][n];
for(int i=0; i<A.length; i++){
for (int j = 0; j<n; j++) {
A[i][j] = (int) (Math.random()*10);
}
}
System.out.println(A[1][n-1]);
System.out.print("Distance between exit i and exit j is: " + distance());
}
public static int distance(){
Scanner input = new Scanner(System.in);
System.out.print("Please enter exit i: ");
int i = input.nextInt();
System.out.print("Please enter exit j: ");
int j = input.nextInt();
return i + j;
}
}
How can I fix it?
Would this help?
int n = input.nextInt();
Random rand = new Random();
int [][] A = new int[2][n];
for (int i = 0; i<n; i++) {
A[0][i] = i+1;
A[1][i] = rand.nextInt(10);
}
Am not too certain about what you mean by:
1 2 3 4 5 6 7 (User's input)
0 2 4 8 9 8 5 (Random numbers)
Do you want users to manually enter "1 2 3 4 5 6 7"?
Eitherway, here's something to help with the printing aspect:
public static void main(String[] args) {
// TODO code application logic here
Scanner input = new Scanner(System.in);
System.out.print("Enter number of exits: ");
int n = input.nextInt();
int [][] A = new int[2][n];
for(int i=0; i<A.length; i++){
for (int j = 0; j<n; j++) {
A[i][j] = (int) (Math.random()*10);
}
}
for(int[] b: A)
{
for(int k: b)
{
System.out.print(k + " ");
}
System.out.println();
}
System.out.print("Distance between exit i and exit j is: " + distance());
}
My program will output a graphical representation of some rows and columns. It asks the users to input the number of rows and columns they want to see the figure for. For example if the user chooses 4 rows and 3 columns, it should print a figure (let's say it's made up of character X) which has 4 rows and 3 columns.
The final output will look like this:
X X X
X X X
X X X
X X X
Now the problem is I can't set the logic in my for loop so that it makes the desired shape. I tried, but couldn't figure it out.
This what I have done so far:
package banktransport;
import java.util.*;
public class BankTransport {
static int NumOfRow;
static int numOfColum;
static Scanner input = new Scanner(System.in);
public static void main(String[] args) {
showRowCol(NumOfRow, numOfColum);
}
public static void showRowCol(int NumOfRow, int numOfColum) {
System.out.println("Enter row: ");
NumOfRow = input.nextInt();
System.out.println("Enter Col: ");
numOfColum = input.nextInt();
System.out.println("");
System.out.println("Visual Representation: ");
//print column and row
for (int i = 0; i < numOfColum; i++) {
System.out.print(" X ");
//System.out.println("");
//for(int j=1; j<(NumOfRow-1);j++){
// System.out.print(" Y ");
//}
}
System.out.println("");
}
}
Try a loop like this:
for ( int i = 0; i < numOfRow; i++ )
{
for ( int j = 0; j < numOfColum; j++ )
{
System.out.print(" X ");
}
System.out.println();
}
Try:
for (int i = 0; i < numOfRow; i++) {
StringBuilder line = new StringBuilder();
for (int j = 0; j < numOfColumn; j++) {
line.append("X ");
}
System.out.println(line.toString());
}
You can also use Apache Commons Lang StringUtils.repeat method (which would prevent you from having a trailing space at the end of the line):
for (int i = 0; i < numOfRow; i++) {
System.out.println(StringUtils.repeat("X", " ", numOfColumn));
}
A link to the assignment:
http://i.imgur.com/fc86hG9.png
I'm having a bit of trouble discerning how to take a series of numbers and apply them to an array without a loop. Not only that, but I'm having a bit of trouble comparing them. What I have written so far is:
import java.util.Scanner;
public class Lottery {
public static void main(String[] args) {
int userInputs[] = new int[5];
int lotteryNumbers [] = new int[5];
int matchedNumbers =0;
char repeatLottery = '\0';
Scanner in = new Scanner (System.in);
do{
System.out.println("Enter your 5 single-digit lottery numbers.\n (Use the spacebar to separate digits): ");
for(int i = 0; i <5; i++ )
userInputs[i] = in.nextInt();
System.out.println("Your inputs: ");
printArray(userInputs);
System.out.println("\nLottery Numbers: ");
readIn(lotteryNumbers);
for(int i=0; i<5; i++) {
System.out.print(lotteryNumbers[i] + " ");
}
matchedNumbers = compareArr(userInputs, lotteryNumbers);
System.out.println("\n\nYou matched " + matchedNumbers + " numbers");
System.out.println("\nDo you wish to play again?(Enter Y or N): ");
repeatLottery = in.next().charAt(0);
}
while (repeatLottery == 'Y' || repeatLottery == 'y');
}
public static void printArray(int arr[]){
int n = arr.length;
for (int i = 0; i < n; i++) {
System.out.print(arr[i] + " ");
}
}
public static void readIn(int[] List) {
for(int j=0; j<List.length; j++) {
List[j] = (int) (Math.random()*10);
}
}
public static int compareArr (int[] list1, int[] list2) {
int same = 0;
for (int i = 0; i <= list1.length-1; i++) {
for(int j = 0; j <= list2.length-1; j++) {
if (list1[i] == list2[j]) {
same++;
}
}
}
return same;
}
}
As you'll notice, I commented out the input line because I'm not quite sure how to handle it. If I have them in an array, I should be able to compare them fairly easily I think. This is our first assignment handling arrays, and I think it seems a bit in-depth for only having one class-period on it; So, please forgive my ignorance. :P
Edit:
I added a new method at the end to compare the digits, but the problem is it compares them in-general and not from position to position. That seems to be the major issue now.
your question isn't 100% clear but i will try my best.
1- i don't see any problems with reading input from user
int[] userInput = new int[5]; // maybe here you had a mistake
int[] lotterryArray = new int[5]; // and here you were declaring your arrays in a wrong way
Scanner scanner = new Scanner(system.in);
for ( int i = 0 ; i < 5 ; i++)
{
userInput[i] = scanner.nextInt();
} // this will populate your array try to print it to make sure
Edit : important in the link you shared about the assignment the compare need to check the value and location so if there are two 5 one in input one in loterry array they need to be in the same location check the assignment again
// to compare
int result = 0 ; // this will be the number of matched digits
for ( int i = 0 ; i < 5 ; i++)
{
if ( userInput[i] == loterryArray[i] )
result++
}
// in this comparsion if the digits are equale in value and location result will be incremented