How to remove trailing white spaces from System.out.println(); Java

How to remove trailing white spaces from System.out.println(); Java - java

This is my code:
import java.util.*;
public class Main {
public static void fill(char mat[][], int x, int y, char prevV, char currV) {
if (x < 0 || x >= mat.length || y < 0 || y >= mat.length)
return;
if (mat[x][y] != prevV)
return;
mat[x][y] = currV;
fill(mat, x + 1, y, prevV, currV);
fill(mat, x - 1, y, prevV, currV);
fill(mat, x, y + 1, prevV, currV);
fill(mat, x, y - 1, prevV, currV);
}
public static void replace(char mat[][]) {
for (int i = 0; i < mat.length; i++)
for (int j = 0; j < mat.length; j++)
if (mat[i][j] == 'O')
mat[i][j] = 'v';
for (int i = 0; i < mat.length; i++)
if (mat[i][0] == 'v')
fill(mat, i, 0, 'v', 'O');
for (int i = 0; i < mat.length; i++)
if (mat[i][mat.length - 1] == 'v')
fill(mat, i, mat.length - 1, 'v', 'O');
for (int i = 0; i < mat.length; i++)
if (mat[0][i] == 'v')
fill(mat, 0, i, 'v', 'O');
for (int i = 0; i <mat.length; i++)
if (mat[mat.length - 1][i] == 'v')
fill(mat, mat.length - 1, i, 'v', 'O');
for (int i = 0; i < mat.length; i++)
for (int j = 0; j < mat.length; j++)
if (mat[i][j] == 'v')
mat[i][j] = 'X';
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int m = sc.nextInt();
char[][] mat = new char[n][m];
for(int i = 0; i < n; i++) {
for(int j = 0; j < m; j++) {
mat[i][j] = sc.next().charAt(0);
}
}
replace(mat);
for(int i = 0; i < n; i++) {
for(int j = 0; j < m; j++) {
System.out.print(mat[i][j] + " ");
}
System.out.println();
}
}
}
The part I am having issues with is the main method, specifically this part:
for(int i = 0; i < n; i++) {
for(int j = 0; j < m; j++) {
System.out.print(mat[i][j] + " ");
}
System.out.println();
}
My problem is at the end of each line there will be a white space because of the + " ".
How can I remove the white space at the end of each line
P.S. if this thread already exists, please link me to it because most of the whitespace solutions are with Strings and just using .trim();

Don't give the space character when its the end of the row.
You could write like this:
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (j < m - 1)
System.out.print(mat[i][j] + " ");
else
System.out.println(mat[i][j]);
}
}

Add a condition for output white space:
for (int j = 0; j < m; j++) {
System.out.print(mat[i][j]);
if (j < m - 1) {
System.out.print(" ");
}
}

besides the answer given, you can do this
for(int i = 0; i < n; i++) {
int j =0; //we move j outside so that it can be accessed later
for( ; j < m -1; j++) { //notice we skip the last entry of the row
System.out.print(mat[i][j] + " ");
}
System.out.println(mat[i][j]); //we add the last entry of the row here.
}
the advantage is that you don't need to do an if check every iteration and there's minimal changes to your current codes.

Related

How to make diamond pattern using java?

How to make this pattern
if input N = 5
Output :
Mine is like this, it become 2N
if input N = 5
Output
Here's my code
int i,j;
for(i = 0; i <= n; i++)
{
for(j = 1; j <= n - i; j++)
System.out.print(" ");
for(j = 1; j <= 2 * i - 1; j++)
System.out.print("*");
System.out.print("\n");
}
for(i = n - 1; i >= 1; i--)
{
for(j = 1; j <= n - i; j++)
System.out.print(" ");
for(j = 1; j <= 2 * i - 1; j++)
System.out.print("*");
System.out.print("\n");
}
What should i fix??

You can check odd numbers in your loop. Please see the following example:
public static void main(String[] args) {
printPattern(5);
}
private static void printPattern(int n) {
int i, j;
for (i = 0; i <= n; i++) {
if (i % 2 != 0) {
for (j = 1; j <= (n - i)/2; j++) {
System.out.print(" ");
}
for (j = 0; j < i; j++) {
System.out.print("*");
}
System.out.println();
}
}
for (i = n - 1; i >= 1; i--) {
if (i % 2 != 0) {
for (j = 1; j <= (n - i)/2; j++) {
System.out.print(" ");
}
for (j = 0; j <i; j++) {
System.out.print("*");
}
System.out.println();
}
}
}

Instead of running these two loops from 0 to N twice. Just run half N/2 in each loop.
Example:
public static void main(String[] args) {
int n = 10;
for (int i = 0; i <= (n / 2 + 1); i++) {
for (int j = 1; j <= n - i; j++) System.out.print(" ");
for (int j = 1; j <= 2 * i - 1; j++) System.out.print("*");
System.out.print("\n");
}
// N/2
for (int i = n / 2 - 1; i >= 1; i--) {
for (int j = 1; j <= n - i; j++) System.out.print(" ");
for (int j = 1; j <= 2 * i - 1; j++) System.out.print("*");
System.out.print("\n");
}
}

How to I draw an upwards pyramid with an array?

I need to draw two pyramids using character in arrays. Upwards and Downwards. I have the downwards pyramid but can't think of the upwards.
I can do the downwards pyramid but can't figure the upwards(normal pyramid).
this is the downward of my code
char [] [] pointDown = new char [length] [length];
for (int i = 0; i < length; i++){
for (int j = 0; j < length; j++) {
if ( i > 0 && j-i<0) {
pointDown[i][j] = ' ';
System.out.print(" ");
}else if ( j >= length-i){
pointDown[i][j] =' ';
System.out.print(" ");
}
else {
pointDown[i][j] = asterik;
System.out.printf("%2s",asterik);
}
}
System.out.println();
}
return pointDown;
}
my attempt of upward pyramid:
char [] [] pointUp = new char [length] [length];
for (int i = 0; i < length; i++){
for (int j = 0; j < length; j++) {
if ( i > (length-1)/2)
{ //bottom half spaces
pointUp[i][j] =' ';
System.out.print("x ");
}else if( j < (length-1)/2 && i < (length-1)){
}
}
System.out.println();
}
return pointUp;
}
3rd update
for (int i = 0; i < length; i++){
for (int j = 0; j < length; j++) {
pointUp[i][j] = ' ';
}
}
int end = length;
int j = 0;
for (int column = 0; column < end; column++) {
for (int row = j; row <= length/2; row++) {
pointUp[row][column] = asterik;
}
j++;
end++;
}
return pointUp;

how to print the below pattern

for the given input I need to print the pattern. For example for input = 6 I have to print:
MMMMMMSDDDDDD
MMMMMSSSDDDDD
MMMMSSSSSDDDD
MMMSSSSSSSDDD
MMSSSSSSSSSDD
MSSSSSSSSSSSD
CSSSSSSSSSSSK
CCSSSSSSSSSKK
CCCSSSSSSSKKK
CCCCSSSSSKKKK
CCCCCSSSKKKKK
CCCCCCSKKKKKK
I have tried but couldn't go further than this could anyone help
public class tgk {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int size = sc.nextInt();
int half = ((2*size)+1)/2;
for (int i = 0; i < size ; i++)
{
for (int j = size; j > i; j--)
{
System.out.print("M");
}
for (int k = half+1 ; k > half - i; k--)
{
System.out.print("S");
}
System.out.println();
}
for(int i = size; i > 0; i--)
{
for (int j = size; j >= i; j--) {
System.out.print("C");
}
for (int k = 0; k < (i * 2 - 1); k++) {
System.out.print("S");
}
System.out.println();
}
}
}
if input = 3 it should be
MMMSDDD
MMSSSDD
MSSSSSD
CSSSSSK
CCSSSKK
CCCSKKK

You can use two sets of for loops to print each half of the pattern. Assuming input variable holds the size of the problem
int input = 3;
for (int i = 0; i < input; i++) {
for (int j = 0; j < input - i; j++) {
System.out.print('M');
}
for (int j = 0; j < 2 * i + 1; j++) {
System.out.print('S');
}
for (int j = 0; j < input - i; j++) {
System.out.print('D');
}
System.out.println();
}
for (int i = input - 1; i >= 0; i--) {
for (int j = 0; j < input - i; j++) {
System.out.print('C');
}
for (int j = 0; j < 2 * i + 1; j++) {
System.out.print('S');
}
for (int j = 0; j < input - i; j++) {
System.out.print('K');
}
System.out.println();
}
will print for input = 3:
MMMSDDD
MMSSSDD
MSSSSSD
CSSSSSK
CCSSSKK
CCCSKKK
and for input = 6:
MMMMMMSDDDDDD
MMMMMSSSDDDDD
MMMMSSSSSDDDD
MMMSSSSSSSDDD
MMSSSSSSSSSDD
MSSSSSSSSSSSD
CSSSSSSSSSSSK
CCSSSSSSSSSKK
CCCSSSSSSSKKK
CCCCSSSSSKKKK
CCCCCSSSKKKKK
CCCCCCSKKKKKK

I don't know why, but I really wanted it to work with only one set of for-loops:
int number = 8;
for (int i = 0; i < number * 2; i++) {
for (int j = 0; j < (number * 2) + 1; j++) {
System.out.print(
i < number && j+i < number ? 'M' :
i < number && j-i > number ? 'D' :
i < number ? 'S' :
i >= number && i-j >= number ? 'C' :
i >= number && j+i >= number*3 ? 'K' :
'S'
);
}
System.out.println();
}
So for 8 (like in the code) it prints:
MMMMMMMMSDDDDDDDD
MMMMMMMSSSDDDDDDD
MMMMMMSSSSSDDDDDD
MMMMMSSSSSSSDDDDD
MMMMSSSSSSSSSDDDD
MMMSSSSSSSSSSSDDD
MMSSSSSSSSSSSSSDD
MSSSSSSSSSSSSSSSD
CSSSSSSSSSSSSSSSK
CCSSSSSSSSSSSSSKK
CCCSSSSSSSSSSSKKK
CCCCSSSSSSSSSKKKK
CCCCCSSSSSSSKKKKK
CCCCCCSSSSSKKKKKK
CCCCCCCSSSKKKKKKK
CCCCCCCCSKKKKKKKK
...or for 3:
MMMSDDD
MMSSSDD
MSSSSSD
CSSSSSK
CCSSSKK
CCCSKKK

Java ArrayIndexOutOfBoundsException (Minesweeper)

I am trying to make a simple minesweeper that plants n*n/3 mines in a n*n board. The mines are marked by *, and blank spaces are marked by 0. (It does not function as a game yet: I'm trying to make the 'answer sheet' of the minesweeper) And please note that I haven't used any methods on purpose.
I am constantly getting an error at the 23rd line:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 15
I have tried for hours to fix this issue, but none seems to work. Can anyone point out what is wrong and how I should fix my code? Thanks.
import java.util.Scanner;
public class Minesweeper {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
char board[][] = new char [n][n]; // makes board of n*n
int a, b;
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board[i].length; j++) {
board[i][j] = '0';
}
}
for (int i = 0; i < n * n / 3; i++) { // '*' is a mine
a = (int)(Math.random() * (n - 1) + 1.0);
b = (int)(Math.random() * (n - 1) + 1.0);
board[a][b] = '*';
}
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board[i].length; j++) {
for (int k = i - 1; k <= i + 1 && k >= 0 && k <= n; k++) {
for (int l = j - 1; l <= j + 1 && l >= 0 && l <= n; l++) {
if (board[k][l] == '*' && !(k == i && l == j)) {
board[i][j] = (char)(Character.getNumericValue(board[i][j]) + 1);
}
}
}
}
}
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board[i].length; j++) {
System.out.println(board[i][j]);
}
}
}
}

for (int k = i - 1; k <= i + 1 && k >= 0 && k <= n; k++) {
for (int l = j - 1; l <= j + 1 && l >= 0 && l <= n; l++) {
It should be k < n and l < n. n is already outside the boundaries.
Also
for (int i = 0; i < n * n / 3; i++) { // '*' is a mine
a = (int)(Math.random() * (n - 1) + 1.0);
b = (int)(Math.random() * (n - 1) + 1.0);
board[a][b] = '*';
}
seems wrong, I think it should be
for (int i = 0; i < n * n / 3; i++) { // '*' is a mine
a = (int)(Math.random() * n);
b = (int)(Math.random() * n);
board[a][b] = '*';
}

Looping Algorithm

How do I make this:
*******
-*****-
--***--
---*---
--***--
-*****-
*******
The following is my code that I have written to try to accomplish the above, but it is not working as expected:
public static void stars(/*int jmlBaris*/) {
for ( int i = 7; i >= 1; i-=2) {
for (int j = 1; j <= i; j++) {
System.out.print("*");
}
System.out.println("");
}
for (int i = 1; i <= 7; i+=2) {
for (int j = 1; j <= i; j++){
System.out.print("*");
}
System.out.println("");
}
}
public static void main(String[] args) {
stars();
}
}

This is how I might write it.
// three loops
public static void stars(int size) {
for (int y = 0; y < size; y++) {
for (int i = 0; i < y && i < size - y - 1; i++)
System.out.print(' ');
for (int i = Math.min(y, size - y - 1); i < Math.max(y + 1, size - y); i++)
System.out.print('*');
System.out.println();
}
}
or
// two loops
public static void stars(int size) {
for (int y = 0; y < size; y++) {
for (int x = 0; x < size; x++)
System.out.print(
(x >= y && x < size - y) ||
(x >= size - y - 1 && x <= y) ? '*' : ' ');
System.out.println();
}
}
or
// one loop
public static void stars(int size) {
for (int i = 0; i < size * size; i++) {
int y = i / size, x = i % size;
System.out.print(
(x >= y && x < size - y) ||
(x >= size - y - 1 && x <= y) ? '*' : ' ');
if (x == size - 1)
System.out.println();
}
}
Note: Whether this uses one, two or three loops, the time complexity is O(N^2). A simple way to determine this is the number of stars produced is O(N^2) no matter how it is done.

I would do something like this with substrings.
String a = "*******"; //7 stars
String blank = " "; //7 spaces
int j = 7;
for (int i = 0; i < 7; i++) {
if (i > j){
System.out.print(blank.substring(0,i));
System.out.println(a.substring(i,j));
}
else{
System.out.print(blank.substring(0,j));
System.out.println(a.substring(j,i));
}
j--;
}
System.out.println(a);
**Previous edit wouldn't have worked. Changes made.
This works.

Try something like this code I compiled on IDEOne (it seems to work, though):
http://ideone.com/9xZ1YB
class Main
{
public static void main(String[] args)
{
stars();
}
static void stars()
{
final int MAX_WIDTH = 7;
for (int i = 0; i < 7; ++i)
{
int width;
if (i < 3) width = MAX_WIDTH - i * 2;
else if (i > 3) width = (i - 3) * 2 + 1;
else width = 1;
// Before spaces
for (int j = 0; j < (MAX_WIDTH - width) / 2; ++j)
{
System.out.print(" ");
}
// Stars
for (int j = 0; j < width; ++j)
{
System.out.print("*");
}
// After spaces
for (int j = 0; j < (MAX_WIDTH - width) / 2; ++j)
{
System.out.print(" ");
}
System.out.println();
}
}
}

For a beginner in algorithms I would recommend you to break down the structure in sub-parts and then try to solve the pattern.
For this specific pattern it could be broken down into several triangles. Each triangle is then solved by different for loops as shown in the image below.
public static void printPattern(int num) {
// this loop generates first 4 lines
for (int i = 0; i < num / 2 + 1; i++) {
// draws the red triangle of '-'
for (int j = 0; j < i; j++) {
System.out.print("-");
}
// draws the green triangle of '*'
for (int j = i; j < num / 2 + 1; j++) {
System.out.print("*");
}
// draws the blue triangle of '*'
for (int j = i + 1; j < num / 2 + 1; j++) {
System.out.print("*");
}
// draws the orange triangle of '-'
for (int j = 0; j < i; j++) {
System.out.print("-");
}
System.out.println();
}
/* this loop generates last 3 lines */
for (int i = 0; i < num / 2; i++) {
// draws the green triangle of '-'
for (int j = i + 1; j < num / 2; j++) {
System.out.print("-");
}
// draws the red triangle of '*'
for (int j = 0; j < i + 2; j++) {
System.out.print("*");
}
// draws the orange triangle of '*'
for (int j = 0; j < i + 1; j++) {
System.out.print("*");
}
// draws the blue triangle of '-'
for (int j = i + 1; j < num / 2; j++) {
System.out.print("-");
}
System.out.println();
}
}
Using similar technique you could generate any pattern.

If I understood you right, your problem is to print indent in lines 2-7.
Imagine same problem with asterisk symbol replaced by 'x' and whitespace replaced by '-'. Then you need to draw
xxxxxxx
-xxxxx-
--xxx--
---x---
--xxx--
-xxxxx-
xxxxxxx
That means you should output 0, 1, 2 space(s) before asterisks in first, second, thrid strings respectively. I let details for you to figure them out.

public static void stars(/*int jmlBaris*/){
String starstr = "*";
String blank = "_";
int spaceBlank;;
for(int i=7; i>=1;i-=2){
spaceBlank = (7-i)*.5;
String starrep = StringUtils.repeat(starstr, i);
String blankrep = StrinUtils.repeat(blank, spacesBlank);
system.out.println(blankrep + starrep + blankrep);
}
for(int j=3 j<=7; j+=2){
spaceBlank = (7-j)*.5;
starrep = StringUtils.repeat(starstr, j);
String blankrep = StrinUtils.repeat(blank, spacesBlank);
system.out.println(blankrep + starrep + blankrep);
}
}
public static void main(String[] args){
stars();
}

You have little missing to put space on your code. I don't care about right space, who can see that? But left space is very important!!
Try this:
public static void stars(/*int jmlBaris*/) {
for ( int i = 7; i >= 1; i-=2) {
for (int k = 0; k < ((7-i) / 2); k++){ /* Missing Here */
System.out.print(" "); /* Missing Here */
} /* Missing Here */
for (int j = 1; j <= i; j++) {
System.out.print("*");
}
System.out.println("");
}
for (int i = 1; i <= 7; i+=2) {
for (int k = 0; k < ((7-i) / 2); k++){ /* Missing Here */
System.out.print(" "); /* Missing Here */
} /* Missing Here */
for (int j = 1; j <= i; j++){
System.out.print("*");
}
System.out.println("");
}
}

int N = 7;
for (int y=0; y<N; y++)
{
for (int x=0; x<N; x++)
System.out.print( (y-x)*(N-y-x-1)<=0 ? '*' : '-');
System.out.println();
}
or, more symmetrically,
int n = 3;
for (int y=-n; y<=n; y++)
{
for (int x=-n; x<=n; x++)
System.out.print( y*y>=x*x ? '*' : '-');
System.out.println();
}

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

How to remove trailing white spaces from System.out.println(); Java - java

Don't give the space character when its the end of the row. You could write like this: for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { if (j < m - 1) System.out.print(mat[i][j] + " "); else System.out.println(mat[i][j]); } }

Add a condition for output white space: for (int j = 0; j < m; j++) { System.out.print(mat[i][j]); if (j < m - 1) { System.out.print(" "); } }

Related

How to make diamond pattern using java?

How to I draw an upwards pyramid with an array?

how to print the below pattern

Java ArrayIndexOutOfBoundsException (Minesweeper)

Looping Algorithm

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