how to reverse the numbers in this pattern [closed] - java

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I wanna make a pattern like this this pattern is similar to flyords triangle but the alternate rows are in reverse order i tried something but couldn't get the expected output
1
3*2
4*5*6
10*9*8*7
11*12*13*14*15
I tried this stuff ,
public static void main(String args[])
{
int count=1;
for(int i=1;i<=5;i++)
{
for(int j=1;j<=i;j++)
{
if(i>j) {
System.out.print(count + "*");
count++;
}else {
System.out.print(count);count++;
}
}System.out.println();
}
}
}
the result i got is,
1
2*3
4*5*6
7*8*9*10
11*12*13*14*15
how to reverse alternate rows :(

You can determine how much to add using the trinary operator on the oddness of the line number and set the correct starting value of that line inside the definition of your for loop:
public static void main(String args[])
{
int currentNumber = 0;
for (int line = 1; line <= 5; currentNumber += (line++))
{
for (int i = 1; i <= line; i++)
{
System.out.print(currentNumber + ((line % 2 == 1) ? i : line + 1 - i));
if (i < line)
System.out.print("*");
}
System.out.println();
}
}

You can start number that would normally be last in that row for every even row. That is your starting number will be i-1 larger that it would normally be, and instead of count++ you count--.
public static void main(String args[])
{
int count=1;
for(int i=1;i<=5;i++)
{
if (i%2 == 0)
{
count += i-1; // there are i numbers on this row, highest is (i-1) larger than lowest
for(int j=1;j<=i;j++)
{
if(i>j) {
System.out.print(count + "*");
count--;
}else {
System.out.print(count);
}
}System.out.println();
count += i // count was lowest number on current row. Increase it to lowest number on next row.
}
else
{
for(int j=1;j<=i;j++)
{
if(i>j) {
System.out.print(count + "*");
count++;
}else {
System.out.print(count);count++;
}
}System.out.println();
}
}
}

int count = 1;
int plus = 0;
for (int i = 1; i <= 10; i++) {
plus = i - 1;
for (int j = 1; j <= i; j++) {
if (i % 2 == 0) {
if (i > j) {
System.out.print(count + plus + "*");
plus-=2;
count++;
} else {
System.out.print(count+plus);
count++;
}
} else {
if (i > j) {
System.out.print(count + "*");
count++;
} else {
System.out.print(count);
count++;
}
}
}
System.out.println();
}

Related

Checking if an array contains two numbers [closed]

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i have just started with Java and facing a problem right now, which i cannot solve after 2hrs of checking code.
When i input :
7 ( as length)
6 3 4 8 3 2 6 (as array)
8 3 (as numbers to check)
it Writes false, but clearly they are included in the exact order.
Please help me trying to understand what the problem is
here is the Code:
import java.util.Scanner;
public class checker {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
int length = scanner.nextInt();
int[] numbers = new int[length];
boolean broken = false;
for (int i = 0; i < numbers.length; i++) {
numbers[i] = scanner.nextInt();
}
int n = scanner.nextInt();
int m = scanner.nextInt();
for (int j = 1; j < length; j++) {
if (numbers[j] == n && numbers[j-1] == m || numbers[j] == m && numbers[j+1] == n || numbers[j] == m && numbers[j-1] == n || numbers[j] == n && numbers[j+1] == m) {
broken = false;
} else {
broken = true;
}
}
if (broken) {
System.out.println("false");
} else {
System.out.println("true");
}
}
}
As you mentioned in a comment, you want to check on {n,m} and {m,n} so why do you have more conditions?
The following is enough:
for (int j = 0; j < length-1; j++) {
if (numbers[j] == n && numbers[j+1] == m || numbers[j] == m && numbers[j+1] == n) {
broken = false;
break;
} else {
broken = true;
}
}
The loop goes from 0 (=first array element) to the last -1 because the if compares with j+1. Once you have found a match you have to break out of the loop otherwise you risk to set broken to false again.
You could also achieve this without using a boolean, check tweaked code below.
import java.util.Scanner;
public class checker {
public static void main(String[] args) {
int howManyValuesPresent = 0;
Scanner scanner = new Scanner(System.in);
System.out.println("Length of array");
int length = scanner.nextInt();
int[] numbers = new int[length];
for (int i = 0; i < numbers.length; i++) {
numbers[i] = scanner.nextInt();
}
int n = scanner.nextInt();
int m = scanner.nextInt();
for(int number: numbers){
if(number == n || number == m){
howManyValuesPresent++;
}
}
if (howManyValuesPresent>0) {
System.out.println("true, Your selected numbers appear: " + howManyValuesPresent + " times in array");
} else {
System.out.println("false, Your selected numbers appear: " + howManyValuesPresent + " times in array");
}
}
}

I need help getting my code to look like this: [closed]

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I need help getting my code output to look like the image below and I am not sure what I am doing wrong and I need to have my code output indented and cant remember how to indent it.
Here is my code currently:
// Fig. 18.3: FactorialCalculator.java
// Recursive factorial method.
public class Assignment_6_1
{
// recursive method factorial (assumes its parameter is >= 0
static StringBuilder s = new StringBuilder();
public static long factorial(long number)
{
if (number == 0) // test for base case
{
return 1;
} else {// recursion step
if (s.length() == 0) {
s.append(number).append("*").append(number - 1);
} else {
for (int i = 0; i < s.length(); i++) {
}
System.out.println(number + " * " + (number - 1) + "!");
s.append("*").append(number).append("*").append(number - 1);
}
return number * factorial(number - 1);
}
}
// output factorials for values 0-21
public static void main(String[] args) {
System.out.println("Hannah Coffey - Lab 6");
// calculate the factorials of 0 through 20
for (int counter = 0; counter < 25; counter++) {
s = new StringBuilder();
System.out.println(counter + "!");
System.out.printf("%d! = %d%n", counter, factorial(counter));
}
}
} // end class FactorialCalculator
Here is what I need it to look like and not sure what I am doing wrong:
Any Help would be greatly appreciated.
My program currently looks like this:
enter image description here
You can pad a String using String.format like this :
String.format("%10s", "foo");
It will create a left padding of 7 spaces 7 + foo.length = 10;
Now, we can render that dynamic like :
public static String padding( int i ) {
return i == 0 ? "" : String.format( "%" + i + "s", "" );
}
Just pass the number of spaces and let the formatter do the job.
for(int i = 5; i >= 0; --i){
System.out.println(padding(i) + "i");
}
Output :
5
4
3
2
1
0
public static long factorial(long number){
if (number == 0) // test for base case
{
return 1;
} else {// recursion step
if (s.length() == 0) {
s.append(number).append("*").append(number - 1);
} else {
String spaces = "";
for (int i = 0; i < number; i++) {
spaces = spaces+" ";
}
if(number==1)
System.out.println(" Base Case: 1");
else {
System.out.println(spaces + "Recursive call:" + number + " * fact(" + (number - 1) + ")");
s.append("*").append(number).append("*").append(number - 1);
}
}
return number * factorial(number - 1);
}
}
public static void main(String[] args) {
System.out.println("Hannah Coffey - Lab 6");
// calculate the factorials of 0 through 20
for (int counter = 0; counter < 25; counter++) {
s = new StringBuilder();
for (int i = 0; i < counter; i++) {
spaces = spaces+" ";
}
System.out.println(spaces+"Recursive call:"+counter + "!");
System.out.printf("%d! = %d%n", counter, factorial(counter));
}
}

counting multiple instances of a char (in a row) in a string [closed]

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No idea why my code isn't working. It keeps returning a value of 1 instead of what I expect.
public class Lab5Example
{
public static void main(String[] args)
{
System.out.println(longestRun("aabbbccd"));
System.out.println("Expected 3");
System.out.println(longestRun("aaa"));
System.out.println("Expected 3");
System.out.println(longestRun("aabbbb"));
System.out.println("Expected 4");
}
public static int longestRun(String s)
{
int count = 1;
int max = 1;
for (int i = 0; i < s.length() - 1; i += 1) {
char c = s.charAt(i);
char current = s.charAt(i + 1);
if (c == current) {
count += 1;
}
else {
if (count > max) {
count = max;
}
current = c;
}
}
return max;
}
}
Debugger isn't working right so I have no idea what's not working.
I see 3 issues.
max = count should be count = max. This is so you store the highest score found thus far.
current = c should be count = 1. This is so you reset the count to start the counting over on the next char sequence.
Outside of your loop you need to do a final check to see if the last char sequence had the highest score. if(count > max) max = count;
This would all look like:
for (int i = 0; i < s.length() - 1; i += 1) {
char c = s.charAt(i);
char current = s.charAt(i + 1);
if (c == current) {
count += 1;
}
else {
if (count > max) {
max = count; // #1
}
count = 1; // #2
}
}
if(count > max) // #3
max = count;
return max;
You want this:
if (count > max) {
max = count;
}
Instead of:
if (count > max) {
count = max;
}
Then at the end before you return add this:
if(count > max)
{
max = count;
}
return max;

Java output in lines of ten

I'm in a beginners java class and I have a quick question about the output statement on my array problem for week 5. So basically I have the core of the program down, but I'm supposed to output the result in lines of ten. I for some reason can not get it to work even with looking at similar posts on here. I'm a beginner and am pretty slow at putting 2 and 2 together when it comes to programming. Once I see it I have that ah-ha! moment and that's how this whole class has gone. I know I have to use the modulus, but in my trial and error I lost my way and have probably done more damage than good. Help would be appreciated.
Here is what I have and as you can tell I was trying something without modulus:
import java.util.*;
public class ArrayLoop
{
public static void main(String args[])
{
double alpha[] = new double[50];
*//Initialize the first 25 elements of the array (int i=0; i<25; i++)//*
for(int i = 0; i < 25; i++)
{
alpha[i]= i * i;
}
*//Initialize the last 25 elements of the array (i=25; i<50; i++)//*
for(int i = 25; i < 50; i++)
{
alpha[i]= 3 * i;
}
*//Print the element of the array*
System.out.println ( "The values are: " );
for (int i = 0; i < 50; i++)
System.out.println ( alpha[i] );
}
*//Print method to display the element of the array*
void print(double m_array[])
{
for(int i = 1; i < m_array.length; i++)
{
if(i % 10 == 0){;
System.out.println();
}else{
System.out.print(" ");
}
}
if (m_array.length % 10 != 0) {
System.out.println();
}
}
}
Um .. this isn't eloquent in the least but I tried to make the fewest changes to your existing code sample.
public class ArrayLoop {
public static void main(String args[]) {
double alpha[] = new double[50];
for (int i = 0; i < 25; i++) {
alpha[i] = i * i;
}
for (int i = 25; i < 50; i++) {
alpha[i] = 3 * i;
}
System.out.println("The values are: ");
for (int i = 0; i < 50; i++) {
System.out.print(alpha[i] + " ");
}
System.out.println();
System.out.println();
for (int i = 1; i < alpha.length; i++) {
if (i != 1 && i % 10 == 0) {
System.out.print(alpha[i - 1] + " ");
System.out.println();
} else {
System.out.print(alpha[i - 1] + " ");
}
}
System.out.print(alpha[49]);
}
}
Edit: A better condition would be ...
for (int i = 0; i < alpha.length; i++) {
if (i > 0 && i % 10 == 9) {
System.out.print(alpha[i] + " ");
System.out.println();
} else {
System.out.print(alpha[i] + " ");
}
}
You have to print the number first then decide whether to print space or newline by checking the modulus:
int arr[] = new int[50];
// Initialize array here
for (int i = 0; i < arr.length; i++) {
System.out.print(arr[i]);
if (i > 0 && (i + 1) % 10 == 0) {
System.out.println();
} else {
System.out.print(" ");
}
}
You have a couple of % 10 snippets in your code so I'm not entirely certain how that's "trying something without modulus" :-)
Having said that, modulus is exactly what you need, as per the following psuedo-code:
count = 0
for each item in list:
if count > 0 and (count % 10) == 0:
print end of line
print item
print end of line
In Java, you would use something like:
public class Test {
static public void main(String args[]) {
for (int i = 0; i < 24; i++) {
if ((i > 0) &&((i % 10) == 0)) {
System.out.println();
}
System.out.print ("" + i * 3 + " ");
}
System.out.println();
}
}
In other words, immediately before you print an item, check to see if it should be on the next line and, if so, output a newline before printing it.
Note that arrays in Java are zero based, so you need to start with an index of zero rather than one in your loops.
Now that's pretty close to what you have so you're on the right track but, for the life of me, I cannot see in your print() method where you actually print the item! That should be number one on your list of things to look into :-)
I urge you to try and work it out from the above text and samples but, if you're still having troubles after more than half an hour or so, the below code shows how I'd do it.
public class Test {
static void print (double m_array[]) {
for (int i = 0; i < m_array.length; i++) {
if ((i > 0) && ((i % 10) == 0))
System.out.println();
System.out.print (m_array[i] + " ");
}
System.out.println();
}
static public void main(String args[]) {
double[] x = new double[15];
for (int i = 0; i < x.length; i++)
x[i] = i * 3;
print (x);
}
}

Java - Printing an empty square using nested loops

I am working on printing a quasi-empty square that looks like the example below (10 asterisks across and 10 down for the 2 columns):
**********
* *
* *
* *
* *
* *
* *
* *
* *
**********
My code cannot dynamically generate squares as specified by the user's input for the number of rows and columns (it is working for 10 rows and 10 columns, but as soon as I change the number to 20, the number of the asterisks does not change. The following is my code:
String STAR = "*";
String star1 = "**********";
int MAX = 10;
for (int row = 0; row <= MAX; row += 1 ) {
for (int col = 0; col <= MAX ; col += 10) {
if (row == 0 && col == 0)
System.out.println(star1);
if (row >= 1 && row <= 4)
System.out.println(STAR + " " + STAR);
if (row == 10 && col == 10)
System.out.println(star1);
}
}
Any help/advice is welcomed regarding the dynamism of the code.
String star = "*";
String space = " ";
int MAX = xxx;
for (int row = 0; row < MAX; row++) {
for (int col = 0; col < MAX; col++) {
if (row == 0 || row == MAX - 1) {
System.out.println(star);
} else if (col == 0 || col == MAX - 1) {
System.out.println(star);
} else {
System.out.println(space);
}
}
}
Look at your nested loop:
for (int col = 0; col <= MAX ; col += 10) {
So when col is 10, you're really only just iterating once... you might as well not have the nested loop at all.
Additionally, both star1 and the string literal with spaces have a fixed number of characters in them, clearly related to the number of columns.
I'm assuming this is homework, so I won't give any more hints than that to start with, but hopefully that'll get you thinking along the right lines...
You should change the 3 occurrences of 10 in your two for loops by the MAX variable, so when the user define another size, your for loop will take his input instead of the 10 value.
Also take a look at your last if statement there where it says if (row == 10 && col == 10) and think about it for a second. Once you have hit 10 rows and 10 columns, you are just going to print your final horizontal line of star1 regardless of what MAX is set too.
Like mentioned above, the nested for loop is unnecessary and can be inefficient if you plan to create larger rectangles in the future (not saying you're going to have to but try to stay away from nested for loops if you can). Instead, just print star1 before your loop begins and after it exits. The body of the loop should be simple enough. Hope this helps.
class Square
{
public static void main(String[] args)
{
String tenStars="**********";
String oneStar="*";
int count=0;
System.out.println(tenStars);
count++;
while(count<=8)
{
System.out.println(oneStar+" "+oneStar);
count++;
}
System.out.print(tenStars);
}
}
this should work
public static void hallowSquare(int side)
{
int rowPos, size = side;
while (side > 0)
{
rowPos = size;
while (rowPos > 0)
{
if (size == side || side == 1 || rowPos == 1 || rowPos == size)
System.out.print("*");
else
System.out.print(" ");
rowPos--;
}
System.out.println();
side--;
}
}
you can use something like this with one user input ... this is working
public static void drawSquare(int size)
{
for(int i=1; i<size ;i++)
System.out.print("*");
System.out.println("");
for(int i=0; i<50 ;i++)
{
System.out.print("*");
for(int j =0; j<size-3; j++)
System.out.print(" ");
System.out.println("*");
}
for(int i=1; i<size ;i++)
System.out.print("*");
}
public static void main(String[] args) {
// TODO Auto-generated method stub
drawSquare(50);
}
you should just create a class in put this inside your class and run it ... I hope this will help you ....
class Star8
{
public static void main(String[] args)
{
for(int i=1;i<=5;i++)
{
for(int j=1;j<=5;j++)
{
if(i==2||i==3||i==4 )
{
System.out.print("* *");
break;
}
else
{
System.out.print("*");
}
}
System.out.println();
}
}
}
Hope this helps, simplify your thinking mate. Think about the axis x and y and work by that logic. Make a nested loop on ur for loop that passes lines, in each case loop the number of
the size of square and print a space, after the nested loop print the "*".
> for (int b=0;b<ans*2-3;b++)
This nested loop has the max value of b because:
remember that while ur printing, each "*" is distanced from the other by a space, and remember u are only counting space between the first and last column. Meaning all space
between x=0 and x=squaresize, therefore max b should be the space between these 2 coords.
which are: squaresize * 2 /the 2 is for the added spaces/ -3/* -3 because u leave out the first coord(x=0),last coord(x=squaresize), AND 1 space added from the former loop.
import java.util.Scanner;
public class AsteriksSquare {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input= new Scanner(System.in);
int ans;
System.out.print("Enter the size of the side of the square: ");
ans=input.nextInt();
String ast="*";
if (ans>0 && ans<21){
for(int i=0;i<=ans-1;i++){
System.out.print("* ");
}
System.out.println("");
for(int i=1;i<=ans-2;i++){
System.out.print("*");
for (int b=0;b<ans*2-3;b++){
System.out.print(" ");
}
System.out.println("*");
}
for(int i=1;i<=ans;i++){
System.out.print("* ");
}
}
}
}
class square1
{
public static void main(String[] args)
{
String star = "*";
String space = " ";
int MAX = 5;
for (int row = 0; row < MAX; row++)
{
for (int col = 0; col < MAX; col++)
{
if (row == 0 || row == MAX - 1)
{
System.out.print(star);
} else if (col == 0 || col == MAX - 1)
{
System.out.print(star);
} else {
System.out.print(space);
}
}
System.out.println();
}
}
}
This code should do the trick.
package javaPackage;
public class Square {
public static void main(String [] args)
{
for (int i=0;i<=10;i++)
{
for (int j=0;j<=10;j++)
{
if(i==0||i==10){
System.out.print("x");
}
else if(j==0||j==10){
System.out.print("x");
}
else{
System.out.print(" ");
}
}
System.out.println();
}
}
}
If the interpreter sees that you're on the first and last line(i=0 and i=10), it will fill the row with x. Else, it will only print a x at the beginning and the end of the row.
you can use below two methods.
1) One with minimal line of code.
for (int i = 0; i <= 9; i++) {
if (i == 0 || i == 9) {
System.out.println("* * * *");
} else {
System.out.println("* *");
}
}
OR
2) With the help of two for loops
for (int i = 0; i <= 9; i++) {
for (int j = 0; j <= 9; j++) {
if (i == 0 || i == 9) {
System.out.print("*");
} else {
if (j == 0 || j == 9) {
System.out.print("*");
} else {
System.out.print(" ");
}
}
}
System.out.println();
}
Thanks,
Stuti
Here's another solution, a more versatile one. It lets you create a hollow rectangle of height "h" and width "w"
private static void hallowSquare(int h, int w)
{
for(int i=1; i<=h; i++)
{
for(int j=1; j<=w; j++)
{
if (j==1|| j==w || i==1 || i==h )
System.out.print("X");
else
System.out.print(" ");
}
System.out.println();
}
}
import java.util.Scanner;
class Star
{
public static void main(String...args)
{
Scanner sc = new Scanner(System.in);
System.out.print("Enter the row : ");
int row=sc.nextInt();
System.out.print("Enter the column : ");
int column=sc.nextInt();
for(int i=1;i<=column;i++)
{
System.out.print("*");
}
for(int i=row-2;i>=1;i--)
{
System.out.println();
System.out.print("*");
for(int k=1;k<=column-2;k++)
{
if(i<1)
{
break;
}
System.out.print(" ");
}
System.out.print("*");
}
System.out.println();
for(int i=1;i<=column;i++)
{
System.out.print("*");
}
}
}
I am hopeful the code below can help, used very simple coding and have the required result.
a=eval(input('Provide the height of the box: '))
b=eval(input('Provide the width of the box: '))
d=a-2
r=b-2
if a >= 1:
print('*'*b)
if a > 1:
for i in range(d):
print('*',end='')
for i in range(r):
print(' ',end='')
print('*')
print('*'*b,end='')
The result is:

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