Java Program to Print Diamond Star Pattern

// Java program to Print Diamond Star Pattern
// Using do-while loop

// Importing input output classes
import java.io.*;

// Main class
public class GFG {

	// Main driver method
	public static void main(String[] args)
	{
		// Declaring and initializing variables

		// Variable initialized to the row where max star
		// should be there as after that they decreases to
		// give diamond pattern
		int number = 7;

		// Diamond starting with single star in first row,so
		// initialized
		int m = 1;

		// Columnar printing
		int n;

		// Outer loop 1
		// Prints the first half diamond
		do {
			n = 1;

			// Inner loop 1
			// Prints space until ++n <= number - m + 1 is
			// false
			do {
				// Print whitespace between
				System.out.print(" ");

			}

			// Condition for inside do-while loop 1
			while (++n <= number - m + 1);

			// Now
			n = 1;

			// Inner loop 2
			// Prints star until ++n <= m * 2 - 1 is false

			do {

				// Print star
				System.out.print("*");
			}

			// Condition for inner do-while loop 2
			while (++n <= m * 2 - 1);

			// A new row requires a new line
			System.out.println();

		}

		// Condition for outer do-while loop 1
		while (++m <= number);

		// Now we are done with printing the upper half
		// diamond.

		// Note: Not to print the bottom row again in lower
		// half diamond printing Hence variable t be
		// initialized should one lesser than number
		m = number - 1;

		// Outer loop 2
		// Prints the second half diamond
		do {
			n = 1;

			// Inner loop 1
			// Prints space until ++n <= number - m + 1 is
			// false
			do {
				// Print whitespace between
				System.out.print(" ");

			} while (++n <= number - m + 1);

			n = 1;

			// Inner loop 2
			// Prints star until ++n <= m * 2 - 1 is false
			do {
				// Prints star
				System.out.print("*");

			} while (++n <= m * 2 - 1);

			// By now done with one row of lower diamond
			// printing so a new line is required
			System.out.println();

		}

		// Condition for outer do-while loop 2
		while (--m > 0);
	}
}