How to make a numbers triangle in Java using loops, numbers starting from right-CodePudding

my project to create a triangle in Java with numbers starting from the right

enter image description here

import java.util.Scanner;
public class Pyramid {

   public static void main(String[] args) {
      Scanner scan = new Scanner(System.in);

      // loop
      for (int i=1; i <= 6; i  ) {
         // space
         for(int j=1; j <= 6-i; j  )
         System.out.print(" ");

         // numbers
         for(int k= 1; k <= i; k  )
         System.out.print(k);

         // new line
         System.out.println();
      }
   }
}

CodePudding user response：

Well the only thing you have to do is change order like you are first adding space and then number instead add number and then space. code -

import java.util.Scanner;
public class Pyramid {
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);

      // loop
      for (int i=1; i <= 6; i  ) {
          // numbers
         for(int k= 1; k <= i; k  )
         System.out.print(k);
         
         // space
         for(int j=1; j <= 6-i; j  )
         System.out.print(" ");
         
         // new line
         System.out.println();

      }
  }
}

Now we get the result -

CodePudding user response：

start k=i then decrement it till k>=1.

for(int k= i; k >=1 ; k--)
     System.out.print(k " ");

output

          1 
        2 1 
      3 2 1 
    4 3 2 1 
  5 4 3 2 1 
6 5 4 3 2 1

CodePudding user response：

import java.util.Scanner;

public class Pyramid {

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    int lines = scanner.nextInt();
    for (int i = 0; i <= lines; i  ) {
        //space
        int spaceNum = lines - i;
        for (int j = 0; j < spaceNum; j  ) {
            System.out.print("  ");
        }
        //numbers
        int numbers = lines - spaceNum;
        for (int j = numbers; j > 0; j--) {
            System.out.print(" "   j);
        }
        System.out.println();
    }

}

}

CodePudding user response：

Here is one way. It uses String.repeat() to pad with leading spaces.

outer loop controls the rows.
Then print the leading spaces
inner loop iterates backwards, printing the value and a space
then print a newline

int rows = 6;
for (int i = 1; i <= rows; i  ) {
    System.out.print("  ".repeat(rows-i));
    for (int k = i; k > 0; k--) {
        System.out.print(k  " ");
    }
    System.out.println();
}

prints

          1 
        2 1 
      3 2 1 
    4 3 2 1 
  5 4 3 2 1 
6 5 4 3 2 1

If you don't want to use String.repeat() then use a loop.