I am new to programming and started with learning c# and now java. I came across a task creating a rhombus where the user inputs the height (odd numbers only) and the char for the rhombus.
I created a for loop for the height and another loop for the characters. Here is my output:
h: 7
c: k
k
jkj
ijkji
hijkjih
ghijkjihg
But I want the output to be:
h: 7
c: k
k
jkj
ijkji
hijkjih
ijkji
jkj
k
How can I develop my logic to apply it to my code.
Here is my code:
Scanner in = new Scanner(System.in);
System.out.print("h: ");
int h = in.nextInt();
System.out.print("c: ");
char c = in.next().charAt(0);
if(h%2==0){
System.out.println("Invalid number!");
return;
}
int count = 1;
int space = 1;
for (int i = 2; i < h; i++)
{
for (int spc = h - space; spc > 0; spc--)
{
System.out.print(" ");
}
if (i < h)
{
space++;
}
else {
space--;
}
for (int j = 0; j < count; j++)
{
System.out.print(c);
if (j < count/2)
{
c++;
}
else {
c--;
}
}
if (i < h)
{
count = count + 2;
}
else {
count = count - 2;
}
System.out.println();
}
Any help is highly appreciated.
Your code contains the following flaws:
count and space variables depend on the values of i and h, which makes it very hard to keep track of and understand. You should avoid hidden dependencies in your code in general
you change the value of c all the time. It makes it very hard to keep track of. You should never change its value
your function is too big
strange values like i = 2, count/2, incrementing by 2
incorrect conditions
You have one loop which increments i. What you need is a second loop which decrements the value of i. And you should also use the same approach for printing of the characters (2 loops for both sides). Let me show you:
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
// load parameters
System.out.print("h: ");
int h = in.nextInt();
System.out.print("c: ");
char c = in.next().charAt(0);
// validate parameters
if (h % 2 == 0) {
System.out.println("Invalid number!");
return;
}
for(int i = 0; i <= h/2; i++) {
printSpaces((h+1) / 2 - i - 1);
printLine(c, i);
System.out.println();
}
for(int i = h/2-1; i >= 0; i--) {
printSpaces((h+1) / 2 - i - 1);
printLine(c, i);
System.out.println();
}
}
private static void printLine(char character, int sideWidth) {
for (int j = sideWidth; j >= 0; j--)
System.out.print((char) (character - j));
for (int j = 1; j <= sideWidth; j++)
System.out.print((char) (character - j));
}
private static void printSpaces(int numberOfSpaces) {
for (int i = 0; i < numberOfSpaces; i++) {
System.out.print(" ");
}
}
which gives you the desired output.
public class Rhombusstar
{
public static void main(String[] args)
{
Scanner sc=new Scanner(System.in);
System.out.println("Enter N : ");
int n=sc.nextInt();
System.out.print("Enter Symbol : ");
char c = sc.next().charAt(0);
for(int i=1;i<=n;i++)
{
for(int j=1;j<=n-i;j++)
{
System.out.print(" ");
}
for(int j=1;j<=n;j++)
{
System.out.print(c);
}
System.out.println();
}
}
}
Related
Help with this question:
Take a positive integer n and form n triangles from stars with their base down of size n each.
For example, for input 3, the following output will be obtained:
* * *
** ** **
*** *** ***
Here's what I've tried.
import java.util.Scanner;
public class ex3 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("enter n");
int n = input.nextInt();
while (n <= 0) {
System.out.println("error");
n = input.nextInt();
}
for (int r = 1; r <= n; r++) {
for (int c = 1; c <= n - r; c++)
System.out.print(" ");
for (int c = 1; c <= r; c++)
System.out.print("*");
System.out.println();
}
}
}
Here's my solution, with explanations in comments
import java.util.Scanner;
class Main {
public static void main(String[] args) {
try(Scanner input = new Scanner(System.in)) {
System.out.println("enter n");
int n = input.nextInt();
while (n <= 0) {
System.out.println("error");
n = input.nextInt();
}
for (int r = 1; r <= n; r++) { // <-- we will have to print n rows
printLine(n, r);
}
}
}
static void printLine(int n, int lineNumber) {
StringBuffer line = new StringBuffer();
for(int i = 0; i < n; i ++) { // <-- each line will have '*'s for n triangles
for(int j = lineNumber; j > 0; j--) { // <-- each line has as many '*'s as its line number, so print those first
line.append("*");
}
for(int j = 0; j < n - lineNumber + 1; j ++) { // <-- we then have to add enough spaces to leave room for the next triangle's '*'s
line.append(" ");
}
}
System.out.println(line.toString()); // <-- print the line we've built so far
}
}
EDIT:
Here's a replit that avoids one of the loops by using a modulo to print an entire line at once, and also uses recursion, for no real reason, in place of the outer-most loop: https://replit.com/#anqit/MicroExtrovertedTrace#Main.java
First, the blanks follow the stars, then, you have to repeat n times the two loops:
for (int r = 1; r <= n; r++) {
for (int t = 1; t <= n; t++) {
for (int c = 1; c <= r; c++)
System.out.print("*");
for (int c = 1; c <= n - r; c++)
System.out.print(" ");
}
System.out.println();
}
You have one for loop that prints out a single triangle of stars using nested for loops. The outer loop is responsible for the number of rows and the inner loops are responsible for printing the spaces and stars.
In my updated code, I added an outer loop that runs n times, and each time it runs, it prints out a triangle of stars. The inner loops are responsible for printing the stars of the triangle and spaces between the triangles.
The main difference is that in your first code, only one triangle is printed, while in my updated code, n triangles are printed. In addition, the indentation of the inner loops has been adjusted to align the triangles correctly on the same line.
import java.util.Scanner;
public class ex3 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("enter n:");
int n = input.nextInt();
while (n <= 0) {
System.out.println("error: please enter a positive number:");
n = input.nextInt();
}
for (int r = 1; r <= n; r++) {
for (int t = 1; t <= n; t++) {
for (int c = 1; c <= r; c++) {
System.out.print("*");
}
for (int i = 0; i < n - r + 1; i++) {
System.out.print(" ");
}
}
System.out.println();
}
}
}
Here is a 3 forloop variant
int n = 4;
for (int i = 1; i <= n; i++) {
StringBuilder b = new StringBuilder("");
for (int s = 0; s < n; s++) {
b.append(s < i ? "*" : " ");
}
String line = b.append(" ").toString();//space between
for (int j = 1; j < n; j++) {
System.out.print(line);
}
System.out.println();
}
produces
> * * *
> ** ** **
> *** *** ***
> **** **** ****
This question already has answers here:
How to make a diamond using nested for loops
(19 answers)
Closed 2 years ago.
I currently have this code which allows me to create the left half of the diamond shape. Is there any way to mirror it to complete the right half. Or a completely different way of creating this shape.
public class diamond {
int size = 0; //sets a starting value for size
static int length = 9;
public static void main(String[] args) {
//creates half of our diamond shape :(
for (int i = 0; i < length; i++) {
int j = length - 1 - i;
for (int k = length / 2; k < length; k++) {
if (k == i || k == j || k == length + 7 + i - j)
System.out.print("X");
else
System.out.print(" ");
}
System.out.println("");
}
}
}
Here is another alternative that takes a slightly different approach.
Since certain widths or lines can't be specified exactly and always have a single middle line, this just prompts for a number.
It calculates spacing and adjusts the field of asterisks within two loops. The first does the top and middle line. The second just does the bottom portion.
String symb = "*";
Scanner input = new Scanner(System.in);
int max = 0;
while (max <= 1) {
System.out.print("Enter a positive no > 1: ");
max = input.nextInt();
}
System.out.println("Width and height are " + (2*max -3)+"\n");
for (int i = 1; i < max; i++) {
System.out.println(" ".repeat(max - i) + symb);
symb += "**";
}
for (int i = 2; i < max; i++) {
System.out
.println(" ".repeat(i) + symb.substring(2 * i));
}
When prompted for and provided an input of 5, this prints.
Enter a positive no > 1: 5
Width and height are 7
*
***
*****
*******
*****
***
*
You can modify this to produce the type of diamond you want.
Below code prints the diamond pattern as per your diagram. This program allows the user to input the no of rows for the diamond and also allows the user to select any shape you want to create your diamond with.
import java.util.*;
public class Main {
public static void main(String[] args) throws IOException {
int n, i, j, space = 1;
System.out.print("Enter the number of rows: ");
Scanner s = new Scanner(System.in);
n = s.nextInt();
System.out.print("Enter Symbol : ");
char c = s.next().charAt(0);
drawDiamond(n,c);
}
static void drawDiamond(int n, char c) {
int i, j, space, k = 0;
for (i = 1; i <= n; i++) {
for (j = 1; j <= n - i; j++) {
System.out.print(" ");
}
while (k != (2 * i - 1)) {
if (k == 0 || k == 2 * i - 2)
System.out.print(c);
else
System.out.print(" ");
k++;
}
k = 0;
System.out.println();
}
n--;
for (i = n; i >= 1; i--) {
for (j = 0; j <= n - i; j++) {
System.out.print(" ");
}
k = 0;
while (k != (2 * i - 1)) {
if (k == 0 || k == 2 * i - 2)
System.out.print(c);
else
System.out.print(" ");
k++;
}
System.out.println();
}
}
}
Sample Output :
Enter the number of rows: 4
Enter Symbol : *
*
* *
* *
* *
* *
* *
*
This Code draws a diamond like your picture but only works with odd numbers.
class Diamond{
int size = 0;
static int length = 9;
public static void main(String[] args) {
int outerSpace = length / 2; //number left to the first x
int count = outerSpace; //same number used to find the mid
int up = 0; //counter for the space between the xx
for (int i = 0; i < length; i++) {
if (i < count) { //this code gets used till you reach the middle
for (int j = 0; j < outerSpace; j++) { //prints space left of x
System.out.print(" ");
}
System.out.print("X");
for (int k = 0; k < up; k++) {
System.out.print(" "); //prints space between the x
}
System.out.println("X");
outerSpace--;
up += 2;
}else{ //code after middle
for (int j = 0; j < outerSpace; j++) {
System.out.print(" ");
}
System.out.print("X");
for (int k = 0; k < up; k++) {
System.out.print(" ");
}
System.out.println("X");
outerSpace++;
up -= 2;
}
}
}
}
To get the exact same design, The input length has to be even number.
public class Main {
private static int legnth = 10;
private static int x = legnth /2;
private static int y = x + 1;
public static void main(String[] args) {
for(int i=1; i <= legnth/2; i++) {
for(int j=1; j <= legnth; j++) {
if(j==x || j==y) {
System.out.print("*");
}else {
System.out.print(" ");
}
}
x--;
y++;
System.out.println("");
}
x+=2;
y-=2;
for(int i=1; i < legnth/2; i++) {
for(int j=1; j < legnth; j++) {
if(j==x || j==y) {
System.out.print("*");
}else {
System.out.print(" ");
}
}
x++;
y--;
System.out.println("");
}
}
}
output
**
* *
* *
* *
* *
* *
* *
* *
**
Here is another solution where you can create a string array for one fourth of the diamond and later manipulate that array to print it into diamond. It can take even or odd both to create a diamond like shape.
static int length=9;
static int n=length/2;
public static void main(String[] args) {
String []arr = new String[n];
for (int i = 0; i < n; i++) {
String space="";
int j = n - i;
for (int k = 0; k < j; k++) {
space=space+" ";
}
arr[i]=space+"X";
}
// To print upper half of diamond
for(int i=0;i<n;i++) {
String upper= arr[i] + arr[n -1 -i].substring(0,arr[n-1-i].length()-2)
+ arr[n -1 -i].substring(1,arr[n -1 -i].length());
System.out.println(upper);
}
// To print middle of the diamond
System.out.println("X" + arr[0].substring(0,arr[0].length()-1)
+arr[0].substring(0,arr[0].length()-1) + "X");
// To print down half of the diamond
for(int i=0;i<n;i++) {
String down= arr[n -1 -i]+arr[i].substring(0,arr[i].length()-2)
+arr[i].substring(1,arr[i].length());
System.out.println(down);
}
}
Here is another solution. It will work for any valid odd integer value given for length.
void createDiamond(int length) {
int n = length / 2;
for (int i = 0; i < length; i++) {
for (int j = 0; j <= length; j++) {
if ((i >= 0 && i <= n && (j == n - i || j == n + 1 + i))
|| (i > n && i < length && (j == i - n || j == length + n - i)))
System.out.print("X");
else
System.out.print(" ");
}
System.out.println();
}
}
Output:
createDiamond(9);
XX
X X
X X
X X
X X
X X
X X
X X
XX
So I'm beginning in the world of java programming language and I'm trying to print a christmas tree of X height. So far its working, but if for example the user input 4, it will print 4 rows + the christmas tree stump, wich mean 5. However, I would like it to be 4 INCLUDING the stump.So far I have this:
public class xmas {
public static void main(String[] args)
{
Scanner scan = new Scanner(in);
out.print("please enter a number: ");
int temp = scan.nextInt();
int x = (temp-1)*2 +1;
int y = x/2;
int z = 1;
for(int i=0; i<temp; i++)
{
for(int j=0; j<=y; j++)
{
out.print(" ");
}
for(int k = 0; k<z; k++)
{
out.print("*");
}
out.println();
y--;
z+=2;
}
for(int i =0; i<=x/2; i++)
{
out.print(" ");
}
out.println("*");
}
}
I don't know how to do that. Thanks!
Try using temp-- just after the input, like that:
int temp = scan.nextInt();
temp--;
Or decreasing your loop condition:
for(int i=0; i<temp-1; i++)
Output in both cases:
*
***
*****
*
If you just subtract one from the input, your christmas tree should be the right size. Here's what it would look like (using the Java style conventions):
public class ChristmasTree {
public static void main(String[] args) {
Scanner scanner = new Scanner(in);
out.print("Please enter a number: ");
int temp = scanner.nextInt() - 1; // note the `- 1`
int x = (temp - 1) * 2 + 1;
int y = x / 2;
int z = 1;
for(int i = 0; i < temp; i++) {
for(int j = 0; j <= y; j++) {
out.print(" ");
}
for(int j = 0; j < z; k++) {
out.print("*");
}
out.println();
y--;
z += 2;
}
for(int i =0; i<=x/2; i++) {
out.print(" ");
}
out.println("*");
}
}
Input: base=2, row = 3
Output:
**
****
********
Input: base=3, row = 3
Output:
***
*********
***************************
I have tried this way, but I spaces aren't printing properly.
import java.util.Scanner;
public class loops {
public static void main(String[] args) {
Scanner s=new Scanner(System.in);
System.out.println("enter base:");
int base = s.nextInt();
System.out.println("enter height:");
int h = s.nextInt();
for (int i = 1; i <= h; i++) {
int num = (int)Math.pow(base, i);
for(int n=h-1; n>i-1; n--) {
System.out.print(" ");
}
for (int j = 0; j < num; j++) {
System.out.print("*");
}
System.out.println("");
}
}
}
import java.util.Scanner;
public class loops {
public static void main(String[] args) {
Scanner s=new Scanner(System.in);
System.out.println("enter base:");
int base = s.nextInt();
System.out.println("enter height:");
int h = s.nextInt();
int spacesNum;
int asterisksNum;
for (int i = 1; i <= h; i++) {
spacesNum = (int) ((Math.pow(base, h) - Math.pow(base, i)) / 2);
asterisksNum = (int) (Math.pow(base, i));
for (int j = 0; j < spacesNum; j++) {
System.out.print(" ");
}
for (int j = 0; j < asterisksNum; j++) {
System.out.print("*");
}
System.out.println();
}
s.close();
}
}
The width of space grows geometrically, just like the width of the rings, but in the opposite direction -- it's decaying. Probably the easiest way to code it is to think about the total width, and what you're taking away from it with each ring.
Your code with that taken into account:
public class loops {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
System.out.println("enter base:");
int base = s.nextInt();
System.out.println("enter height:");
int h = s.nextInt();
int width = (int) Math.pow(base, h); // Note the total width.
for (int i = 1; i <= h; i++) {
int num = (int) Math.pow(base, i);
// The space is half of what's left after removing the ring.
for(int j = 0; j < (width - num)/2; j++) {
System.out.print(" ");
}
for (int j = 0; j < num; j++) {
System.out.print("*");
}
System.out.println("");
}
}
}
Your code calls System.out.print method exponential times, one call per character.
Also, System.out.println is invoked in every iteration which causes the underlying stream to flush. (refer links from michaelt in the comments).
This SO answer is a good reference.
This is NOT good approach because:
h number of I/O operations are performed, which is expensive.
So many method invocations of print and println reduces the readability of the code.
Compose the strings in a separate method and use System.out.print only for printing.
Please refer the code below:
public static void main(String[] args) {
//your code here
int totalWidth = (int) Math.pow(base, h);
String output = "";
for (int i = 1; i <= h; i++) {
int numOfStars = (int) Math.pow(base, i);
int numOfSpace = (int) ((totalWidth - numOfStars) / 2);
output += composeString(' ', numOfSpace).concat(composeString('*', numOfStars ).concat("\n"));
}
System.out.println(output);
}
//Method to create String with same character repeated X number of times
public static String composeString(char character, int x) {
StringBuilder buf = new StringBuilder(x);
while (buf.length() < x) {
buf.append(character);
}
return buf.toString();
}
So I was assigned to make a diamond with asterisks in Java and I'm really stumped. Here's what I've come up with so far:
public class Lab1 {
public static void main(String[] args) {
for (int i = 5; i > -5; i--) {
for (int j = 0; j < i; j++) {
System.out.print(" ");
}
for (int j = 0; j >= i; j--) {
System.out.print(" ");
}
System.out.println("*");
}
}
}
In order to make a diamond you need to set spaces and stars in shape. I have made this simple program using only nested loops since I am a beginner.
public class Diamond {
public static void main(String[] args) {
int size = 9,odd = 1, nos = size/2; // nos =number of spaces
for (int i = 1; i <= size; i++) { // for number of rows i.e n rows
for (int k = nos; k >= 1; k--) { // for number of spaces i.e
// 3,2,1,0,1,2,3 and so on
System.out.print(" ");
}
for (int j = 1; j <= odd; j++) { // for number of columns i.e
// 1,3,5,7,5,3,1
System.out.print("*");
}
System.out.println();
if (i < size/2+1) {
odd += 2; // columns increasing till center row
nos -= 1; // spaces decreasing till center row
} else {
odd -= 2; // columns decreasing
nos += 1; // spaces increasing
}
}
}
}
As you can see nos is the number of spaces. It needs to be decreased until the center row, and the number of stars needs to be increased but after the center row it's the opposite, i.e spaces increase and stars decrease.
size can be any number. I set it to 9 over here so I will have a size 9 star that is 9 rows and 9 columns max... number of space (nos) will be 9/2 = 4.5 .
But java will take it as 4 because int can not store decimal numbers and the center row will be 9/2 + 1 = 5.5, which will result in 5 as int.
So first you will make rows... 9 rows hence
(int i=1;i<=size;i++) //size=9
then print spaces like I did
(int k =nos; k>=1; k--) //nos being size/2
then finally stars
(int j=1; j<= odd;j++)
once the line ends...
You can adjust stars and spaces using an if condition.
for (int i = 0; i < 5; i++)
System.out.println(" *********".substring(i, 5 + 2 * i));
for (int i = 5; i > 0; i--)
System.out.println(" **********".substring(i - 1, 5 + (2 * i) - 3));
Note: Using Count Global variable we can manage space as well as star increment and decrement.
import java.util.*;
public class ParamidExample {
public static void main(String args[]) {
System.out.println("Enter a number");
Scanner sc = new Scanner(System.in);
int no = sc.nextInt();
int count = 1;
for (int i = 1; i <= 2 * no - 1; i++) {
for (int j = count; j <= no; j++) {
System.out.print(" ");
}
for (int k = 1; k <= count * 2 - 1; k++) {
System.out.print("* ");
}
if (i < no)
count++;
else
count--;
System.out.println("");
}
}
}
public class MyDiamond {
public static void main(String[] args) {
//Length of the pyramid that we want.151 is just an example
int numRows = 151;
//midrow is the middle row and has numRows number of *
int midrow = (numRows + 1) / 2;
int diff = 0;
for (int i = 1; i < numRows + 1; i++) {
for (int j = 1; j < numRows + 1; j++) {
if (((midrow - diff) <= j && (j <= midrow + diff))) {
System.out.print("*");
} else {
System.out.print(" ");
}
}
System.out.println();
if (i < midrow) {
diff++;
} else {
diff--;
}
}
}
}
public class Diamond {
//Size of the diamond
private int diagonal;
public Diamond(int diagonal) {
this.diagonal = diagonal;
}
public void drawDiamond() {
int n = diagonal;
for (int i = n / 2; i >= -n / 2; i--) {
for (int k = 0; k < i; k++) {
System.out.print(" ");
}
for (int j = 1; j <= (n - i * 2) && i >= 0; j++) {
System.out.print("*");
}
for (int k = 1; k <= -i && i < 0; k++) {
System.out.print(" ");
}
for (int j = (n / 2) * 2 + 2 * i; j >= -(n % 2 - 1) && i < 0; j--) {
System.out.print("*");
}
System.out.println();
}
}
public static void main(String[] args) {
//You pass diamond size here in the constructor
Diamond a = new Diamond(21);
a.drawDiamond();
}
}
The main problem is parity of diagonal.
If it's even you can't properly draw top asterisk. So there is 2 types of diamonds - with even and odd diagonal (with 2 and 1 asterisk at the top).
I can see what you are trying to do and this is a pretty neat way to think about the diamond.
You will have some issues with the j counter when i goes negative..look at how to use Math.abs()
Also try writing some pseudo code in basic steps with comments to get the pattern clear:
//print 5 spaces + 1 star
//print 4 spaces + 2 stars
//print 3 spaces + 3 stars
//print 2 spaces+ 4 stars
.
.
.
//print 5 spaces + 1 star
Then, literally substitute variables (j and i) for the numbers.
You now have a model. This is often the hardest part in programming..getting the model right. Only jump into coding when you have a good idea for how the model works.
Once you have the variables substituted, you can try to convert the whole thing into an automated loop.
import java.util.Scanner;
public class MakeDiamond {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while (true) {
System.out.println("Let's Creat Diamonds");
System.out.println("If number increases Diamonds gets bigger. Please input number lager than 1 : ");
int user_input = sc.nextInt(); //gets user's input
System.out.println("");
int x = user_input;
int front_space = -5;
for (int i = 0; i < 2 * user_input + 1; i++) {
for (int a = front_space; a < Math.abs(i - user_input); a++) {
System.out.print(" "); //Change a bit if diamonds are not in good shape
}
if (i < user_input + 1) {
for (int b = 0; b < 2 * i + 1; b++) {
System.out.print("* "); //Change a bit if diamonds are not in good shape
}
} else if (i > user_input) {
for (int c = 0; c < 2 * x - 1; c++) {
System.out.print("* "); //Change a bit if diamonds are not in good shape
}
x--;
}
System.out.print('\n');
}
System.out.println("\nRun Again? 1 = Run, 2 = Exit : ");
int restart = sc.nextInt();
System.out.println("");
if (restart == 2) {
System.out.println("Exit the Program.");
System.exit(0);
sc.close();
}
}
}
}
When making diamonds with while or for loops.
I think using 'Math.abs' will be the simplest way to make it.
You can put number by Scanner, and when input number increases diamonds will get bigger.
I used Eclipse to make this program.
so, the Space will be differ by your running environment. like another IDE, CMD or Terminal. if diamonds are not in good shape. Just change spaces.
package com.DiamondPrintingProgram;
import java.util.Scanner;
public class DiamondPrintingProgram {
public static void main(String[] args) {
int num = getInput();
int middle = (int) num / 2 + 1;
printOutput(num,middle);
}
public static int getInput() {
Scanner sc = new Scanner(System.in);
int num;
System.out.print("Enter a odd number: ");
while (true) {
num = sc.nextInt();
if (num % 2 != 0) {
break;
}
System.out.print("Please Enter a ODD NUMBER: ");
}
return num;
}
private static void printOutput(int num, int middle){
char asterisk = '*';
for (int j = 0; j < num; j++) {
for (int i = 1; i <= num; i++) {
if (j < middle) {
if ((i < (middle - j) || i > (middle + j))) {
System.out.print(' ');
} else {
System.out.print(asterisk);
}
} else {
if ((i < (j - middle + 2)) || (i > (2 * num - j - middle))) {
System.out.print(' ');
} else {
System.out.print(asterisk);
}
}
}
System.out.println();
}
}
}
I have the exact classwork in my university which also requires me to finish it in 3 for loops.
And this is how I did it.
In a simple way of explanation, I divide the diamond into two parts.
no. of lines
no. of spaces
no. of stars
total no. of slots
1
4
1
5
2
3
3
6
3
2
5
7
4
1
7
8
5
0
9
9
6
1
7
8
7
2
5
7
8
3
3
6
9
4
1
5
I want to find the no. of slots and the no. of spaces with each line, then allocating the no. of stars would be really easy.
And considering the no. of slots, line 1 - 5 and line 6 - 9 would become two separate groups(i.e. middleLine).
The equation of the no. of slots of the first half would be numberOfLines(i.e. i) + (middleLine - 1) where middleLine - 1 would be 4 when the maxNumberOfLines is 9.
The equation of the no. of slots of the last half would be middleLine(i.e. replacement of I) + (middleLine - 1)(i.e. same as above) - (i - middleLine) where i - middleLine would be -1 when i = 6.
And for the space, the first half would be middleLine - i and last half would be i - middleLine, which are exactly in a negative relationship(or symmetrical regarding their slopes).
public class printOutDiamondWith3Loops {
public static void main(String[] args) {
int userInput = 9;
double maxNumberOfLines = userInput;
// double type is used instead of integer type in order to prevent removal of remainder when a division performed.
double middleLine = Math.ceil(maxNumberOfLines/2);
// Print out the diamond.
for (int i = 1; i <= maxNumberOfLines; i++) {
// Determine the number of lines, which is also the maximum number of slots (the line in the middle).
if (i <= middleLine) {
// Separate the whole diamond into two parts(as mentioned above).
for (int j = 1; j <= i + ((middleLine - 1)); j++) {
// Determine the no. of slots in each line from line 1 to 5.
if (j <= middleLine - i) {
// Determine the no. of spaces and stars.
System.out.print(" ");
} else {
System.out.print("*");
}
}
} else { // i > middleLine
for (int k = 1; k <= (middleLine + (middleLine - 1)) - (i - middleLine); k++) {
// Determine the no. of slots in each line from line 6 to 9.
// For better understanding, I did not simplify the above condition.
// Noticeably, the first middleLine in above for loop is a replacement of i.
if (k <= i - middleLine) {
// Determine the no. of spaces and stars.
System.out.print(" ");
} else {
System.out.print("*");
}
}
}
System.out.println();
}
}
With such a framework, it is much easier to make further changes, such as letting the user input the no. of lines they want.
Hope this answer could help you.
I could lend you a more detailed version of my work, though not necessarily in need(the above explanation already explains the concepts): print-Out-Diamond-With-3-Loops-Advanced-Version.java
You can print a diamond of asterisks (mathematical operators) as follows:
int m = 4;
int n = 4;
for (int i = -m; i <= m; i++) {
for (int j = -n; j <= n; j++) {
int val = Math.abs(i) + Math.abs(j);
System.out.print(val > Math.max(m, n) ? " " : "∗");
if (j < n) {
System.out.print(" ");
} else {
System.out.println();
}
}
}
Output:
∗
∗ ∗ ∗
∗ ∗ ∗ ∗ ∗
∗ ∗ ∗ ∗ ∗ ∗ ∗
∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗
∗ ∗ ∗ ∗ ∗ ∗ ∗
∗ ∗ ∗ ∗ ∗
∗ ∗ ∗
∗
Try this
public class Main {
public static void main(String[] args) {
int n = 50;
int space = n - 1;
for (int i = 0; i < n; i++) {
for (int j = 0; j < space; j++) {
System.out.print(" ");
}
for (int j = 0; j <= i; j++) {
System.out.print("* ");
}
System.out.println("");
space--;
}
space = 0;
for (int i = n; i > 0; i--) {
for (int j = 0; j < space; j++) {
System.out.print(" ");
}
for (int j = 0; j < i; j++) {
System.out.print("* ");
}
System.out.println("");
space++;
}
}
}
java-11
Using String#repeat introduced as part of Java-11, you can do it using a single statement inside a single loop.
public class Main {
public static void main(String[] args) {
final int MID_ROW_NUM = 5;
for (int i = 1 - MID_ROW_NUM; i < MID_ROW_NUM; i++) {
System.out.println(" ".repeat(Math.abs(i)) + "*".repeat((MID_ROW_NUM - Math.abs(i)) * 2 - 1));
}
}
}
Output:
*
***
*****
*******
*********
*******
*****
***
*
By changing the space, you can also print a variant of the diamond:
public class Main {
public static void main(String[] args) {
final int MID_ROW_NUM = 5;
for (int i = 1 - MID_ROW_NUM; i < MID_ROW_NUM; i++) {
System.out.println(" ".repeat(Math.abs(i)) + "* ".repeat((MID_ROW_NUM - Math.abs(i)) * 2 - 1));
}
}
}
Output:
*
* * *
* * * * *
* * * * * * *
* * * * * * * * *
* * * * * * *
* * * * *
* * *
*
import java.util.Scanner;
public class Diamond {
/**
* #param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in = new Scanner(System.in);
int input = in.nextInt();
int min = 1;
for (int i = 0; i < input; i++) {
for (int j = input - 1; j > i; j--) {
System.out.print(" ");
}
for (int k = 0; k < min; k++) {
if (k % 2 == 0) {
System.out.print("*");
} else {
System.out.print(".");
}
}
min += 2;
System.out.println();
}
int z = input + input - 3;
for (int i = 1; i < input; i++) {
for (int j = 0; j < i; j++) {
System.out.print(" ");
}
for (int k = 0; k < z; k++) {
if (k % 2 == 0) {
System.out.print("*");
} else {
System.out.print(".");
}
}
z -= 2;
System.out.println();
}
}
}
This should work. You probably only need most of the methods and printDiamond(_);
import java.util.Scanner;
public class StarsTry {
public static void main(String[] args) {
int reader;
Scanner kBoard = new Scanner(System.in);
do {
System.out.println("Insert a number of rows: ");
reader = kBoard.nextInt();
printDiamond(reader);
} while (reader != 0);
}
public static void printStars(int n) {
if (n >= 1) {
System.out.print("*");
printStars(n - 1);
}
}
public static void printTopTriangle(int rows) {
int x = 1;
for (int j = (rows - 1); j >= 0; j--, x += 2) {
printSpaces(j);
printStars(x);
System.out.print("\n");
}
}
public static void printSpaces(int n) {
if (n >= 1) {
System.out.print(" ");
printSpaces(n - 1);
}
}
public static void printBottomTriangle(int rows, int startSpaces) {
int x = 1 + (2 * (rows - 1));
for (int j = startSpaces; j <= (rows) && x > 0; j++, x -= 2) {
printSpaces(j);
printStars(x);
System.out.print("\n");
}
}
public static void printBottomTriangle(int rows) {
int x = 1 + (2 * (rows - 1));
for (int j = 0; j <= (rows - 1) && x > 0; j++, x -= 2) {
printSpaces(j);
printStars(x);
System.out.print("\n");
}
}
public static void printDiamond(int rows) {
printTopTriangle((int) rows / 2 + 1);
printBottomTriangle((int) rows / 2, 1);
}
}
import static java.lang.System.out;
import java.util.Scanner;
public class Diamond {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int row = sc.nextInt();
sc.close();
Diamond d = new Diamond();
d.upperDiamond(row);
d.lowerDiamond(row - 2);
}
public void upperDiamond(int a) {
for (int i = 0; i < a; i++) {
for (int j = a - 1; j > i; j--)
out.print(" ");
for (int k = 0; k < 2 * i - 1; k++)
out.print("*");
out.print("\n");
}
}
public void lowerDiamond(int b) {
for (int i = 0; i < b; i++) {
for (int j = 0; j <= i; j++)
out.print(" ");
for (int k = 0; k < 2 * (b - i) - 1; k++)
out.print("*");
out.print("\n");
}
}
}
public class Main {
public static void main(String[] args) {
int number = 23,l =1,diff = 1,rem = number/2,rep = 0;
for(int i=1;i<=number;i++){
if(i < number/2 +1){
for(int k=rem;k>=1;k--)
System.out.print(" ");
for(int j=1;j<=l;j++)
System.out.print("*");
diff = 2;
rem -= 1;
}
if(i >= number/2 +1){
for(int k=0;k<rep;k++)
System.out.print(" ");
for(int j=1;j<=l;j++)
System.out.print("*");
diff =3;
rep += 1;
}
System.out.println();
l = diff == 2 ? (l + 2) : (l - 2);
}
}
}
//Suitable for only Odd numbers...
public class Main {
private static int l =1;
public static void main(String[] args) {
int number =9;
for(int i=1;i<=2*number -1;i++){
if(i<=number){
for(int j=1;j<=(number-i);j++)
System.out.print(" ");
for(int j=1;j<=i;j++)
System.out.print("* ");
}
if(i>number){
for(int j=1;j<=i-number;j++)
System.out.print(" ");
for(int j=1;j<=number-l;j++)
System.out.print("* ");
l += 1;
}
System.out.println();
}
}
}
class Inc_Dec {
public static void main(String[] args) {
int le = 11;
int c = 0;
int j1 = (le / 2) + 1;
int j2 = le - j1;
for (int i = 1; i <= le; i++) {
if (c < j1) {
for (int k = (j1 - i); k > 0; k--) {
System.out.print(" ");
}
for (int j = 1; j <= i; j++) {
System.out.print("*" + " ");
}
c++;
System.out.println();
} else {
for (int k = (i - j1); k > 0; k--) {
System.out.print(" ");
}
for (int j = (le - i + 1); j > 0; j--) {
System.out.print("*" + " ");
}
System.out.println();
}
}
}
}
package practice;
import java.util.Scanner;
public class Practice {
public static void main(String[] args) {
for (int i = 0; i <= 10; i++) {
if (i <= 5) {
for (int k = 1; k <= 5 - i; k++) {
System.out.print(" ");
}
for (int j = 0; j <= i; j++) {
System.out.print(" *");
}
}
if (i > 5) {
for (int k = 0; k <= i - 6; k++) {
System.out.print(" ");
}
for (int j = 0; j <= 10 - i; j++) {
System.out.print(" *");
}
}
System.out.println();
}
}
}