Question

Write program in Java that produces the number pyramids as shown below:

Enter the number of lines: 8 2 1 2 3 2 1 2 3 4 3 2 1 2 3 4 5 43 2 1 2 3 4 5 6 5 4 3 212 3 4 5 6 7654 3 2 1 2 3 4 5 6 7 8 7 6 5 4 3 2 1 2 3 4 5 6 78 Enter the number of lines: 10 7 6 5 4 3 2 1 2 3 4 5 6 7 10 9 8 7 6 5 4 3 2 1 2 3 4 5 6 7 8 9 10

The programs must prompt the user for how many lines to generate. Your program must be able to generate properly formatted output regardless of the number of lines requested. Notice that the formatting of the output is based upon the maximum number generated in each of the pyramids. The number generated will not be larger than a Long.

You can convert a number to a string like: String str = "" + value;

The format specifier for formatted output (System.out.printf) can be a String variable. You'll need to do this to make sure the output is formatted based on the size of the numbers.

Answer 1

import java.util.Scanner;

class Main {
public static void main(String[] args) {
  
// TAKING user input of a number
System.out.print("Enter the number of lines: ");
Scanner sc = new Scanner(System.in);
long n = sc.nextLong();
  
long i, j;
  
// for numner of lines
for(i=1; i<=n; i++)
{
// for number of spaces at starting
for(j=1; j<= n-i; j++)
{
System.out.print(" ");
}
  
// for first half of the numbers to be printed
for(j=i; j>1; j--)
{
System.out.printf("%-3d",j);
}
  
// for second half of the numbers to be printed
for(j=1; j<=i; j++)
{
System.out.printf("%-3d",j);
}
  
// printing a line
System.out.println();
}
}
}

/*SAMPLE OUTPUTS

Enter the number of lines: 8 2 1 2 3 2 1 2 3 4 3 2 1 2 34 5432 1 2 345 6543 2 1 2 3456 7654 3 21 2 3456 7 87654321 2 345678

*/

Enter the number of lines: 19 4 3 2 1 2 3 4 5 4 3 2 1 2 3 45 6 5 4 3 2 1 2 3 456 7 6 5 432 1 2 3 45 6 7 8 7 6 5 4 3 2 1 2 3 4 5 6 78 10 9 8 76 5 43 2 1 2 3 456 789 10