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Friday, 19 August 2016

Chapter 6 Exercise 6, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

*6.6 (Display patterns) Write a method to display a pattern as follows:

                    1
                 2 1
              3 2 1
...
n n-1 ... 3 2 1

The method header is
public static void displayPattern(int n)

import java.util.Scanner;
 
public class ProgrammingExercise6_6 {
 
 public static void main(String[] args) {
 
  System.out.print("Enter the number of lines:");
  Scanner input = new Scanner(System.in);
 
  // get the total number of lines n.
  int n = input.nextInt();
  displayPattern(n);
 }
 
 public static void displayPattern(int n) {
 
  for (int i = 1; i <= n; i++) {
   // printing spaces, 2 at a time from j=1 to j= n-i
   for (int j = 1; j <= (n - i); j++) {
         
    //Using loop handle multiple digit number
    //loop to find out the number of digit
    //Number to printed on this row is (n-(j-1))
    int numberOfDigit=0;
    int remainder = n-(j-1);
    while (remainder!=0) {
     numberOfDigit++;
     remainder /=10; 
    }
    //Print additional spaces-start at -1 to print a space between column 
    for (int k = -1; k < numberOfDigit; k++) {
     System.out.print(" ");
    }
     
   }
    
   
 
   // Printing number decrementally from line number i to 1
   for (int j = i; j >= 1; j--) {
    System.out.print(j + " ");
     
   }
   System.out.println();
 
  }
 }
 
}

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