public class LoopDemo {
	public static void main(String[] args) {
		//displayBlastoff();
		//displayGrid();
		//displayTriangle();
		//displayNumTriangle();
		//displayNumSequence();
		displayDotsNums();
	}
	
	// display the following text using a loop:
	// T-minus 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, blastoff!
	// Note that loop bounds can be any expression.
	public static void displayBlastoff() {
		System.out.print("T-minus ");
		for(int i = 10; i >= 1; i++) {
			System.out.print(i + ", ");
		}
		System.out.print("blastoff!");

	}
	
	/* display the following grid of stars using for loops:
	 	**********
		**********
		**********
		**********
		**********
	*/
	public static void displayGrid() {
		for(int i = 1; i <= 5; i++) {
			for(int j = 1; j <= 10; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
	}

	/*
	
	*
	**
	***
	****
	*****
	
	*/
	public static void displayTriangle() {
		for(int i = 1; i <= 5; i++) {
			for(int j = 1; j <= i; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
	}
	
	/*
	1
	22
	333
	4444
	55555
	*/
	public static void displayNumTriangle() {
		for(int i = 1; i <= 5; i++) {
			for(int j = 1; j <= i; j++) {
				System.out.print(i);
			}
			System.out.println();
		}
	}
	
	/*
	Mapping loop counter to number sequences
	17 13 9 5 1
	
	count		number	count * -4		count * -4 + 21
	1			17			-4					17
	2			13			-8					13
	3			9			-12				9
	4			5			-16				5
	5			1			-20				1
	*/
	public static void displayNumSequence() {
		for(int count = 1; count <= 5; count++) {
			System.out.print(count * -4 + 21 + " ");
		}
	}
	
	/* 
	Mapping complex patterns to loop counters
	....1
	...2
	..3
	.4
	5
	for each line: print dots, print a number
	line		dots		number		line * -1		line * -1 + 5
	1			4			1				-1					4
	2			3			2				-2					3
	3			2			3				-3					2
	4			1			4				-4					1
	5			0			5				-5					0
	
	How many dots on each line?  line * -1 + 5 dots
	*/
	public static void displayDotsNums() {
		for(int line = 1; line <= 5; line++) {
			for(int j = 1; j <= line * -1 + 5; j++) {
				System.out.print(".");
			}
			System.out.println(line);
		}
	}
}