Question

3.24 Program: Drawing a half arrow (Java) This program outputs a downwards facing arrow composed of a rectangle and a right triangle. The arrow dimensions are defined by user specified arrow base height, arrow base width, and arrow head width. (1) Modify the given program to use a loop to output an arrow base of height arrowBaseHeight. (1 pt) (2) Modify the given program to use a loop to output an arrow base of width arrowBaseWidth. Use a nested loop in which the inner loop draws the *’s, and the outer loop iterates a number of times equal to the height of the arrow base. (1 pt) (3) Modify the given program to use a loop to output an arrow head of width arrowHeadWidth. Use a nested loop in which the inner loop draws the *’s, and the outer loop iterates a number of times equal to the height of the arrow head. (2 pts)

Answer 1

Answer:

Here is the JAVA program:

import java.util.Scanner; // to get input from user

public class DrawHalfArrow{ // start of the class half arrow

public static void main(String[] args) { // starts of main() function body

    Scanner scnr = new Scanner(System.in); //reads input

int arrowBaseHeight = 0; // stores the height of arrow base

int arrowBaseWidth  = 0; // holds width of arrow base

int arrowHeadWidth = 0; // contains the width of arrow head

// prompts the user to enter arrow base height, width and arrow head width

System.out.println("Enter arrow base height: ");

arrowBaseHeight = scnr.nextInt(); // scans and reads the input as int

System.out.println("Enter arrow base width: ");

arrowBaseWidth = scnr.nextInt();

/* while loop to continue asking user for an arrow head width until the value entered is greater than the value of arrow base width */

while (arrowHeadWidth <= arrowBaseWidth) {

    System.out.println("Enter arrow head width: ");

    arrowHeadWidth = scnr.nextInt(); }

//start of the nested loop

//outer loop iterates a number of times equal to the height of the arrow base

 for (int i = 0; i < arrowBaseHeight; i++) {

//inner loop prints the stars asterisks

      for (int j = 0; j <arrowBaseWidth; j++) {

          System.out.print("*");        } //displays stars

          System.out.println();          }

//temporary variable to hold arrowhead width value

int k = arrowHeadWidth;

//outer loop to iterate no of times equal to the height of the arrow head

for (int i = 1; i <= arrowHeadWidth; i++)

{     for(int j = k; j > 0; j--)     {//inner loop to print stars

       System.out.print("*");    } //displays stars

   k = k - 1;

   System.out.println(); } } } // continues to add more asterisks for new line

Explanation:

The program asks to enter the height of the arrow base, width of the arrow base and the width of arrow head. When asking to enter the width of the arrow head, a condition is checked that the arrow head width arrowHeadWidth should be less than or equal to width of arrow base arrowBaseWidth. The while loop keeps iterating until the user enters the arrow head width larger than the value of arrow base width.

The loop is used to output an arrow base of height arrowBaseHeight. So point (1) is satisfied.

The nested loop is being used which as a whole outputs an arrow base of width arrowBaseWidth. The inner loop draws the stars and forms the base width of the arrow, and the outer loop iterates a number of times equal to the height of the arrow. So (2) is satisfied.

A temporary variable k is used to hold the original value of arrowHeadWidth so that it keeps safe when modification is done.

The last nested loop is used to output an arrow head of width arrowHeadWidth. The inner loop forms the arrow head and prints the stars needed to form an arrow head. So (3) is satisfied.

The value of temporary variable k is decreased by 1 so the next time it enters  the nested for loop it will be one asterisk lesser.

The screenshot of output is attached.