4.6.5 The Worm CodeHS Answers

The common answer for the 4.6.5 The Worm CodeHS is:

NUM_CIRCLES = 15
# This graphics program should draw a worm.
# A worm is made up of NUM_CIRCLES circles.
# Use a for loop to draw the worm,
# centered vertically in the screen.
# Also, be sure that the worm is still drawn across
# the whole canvas, even if the value of NUM_CIRCLES is changed.
radius = (get_width() / NUM_CIRCLES / 2)
x = radius
for i in range(NUM_CIRCLES):
circ = Circle(radius)
if i % 2 == 0:
circ.set_color(Color.red)
else:
circ.set_color(Color.green)
circ.set_position(x, get_height() / 2)
add(circ)
current_spot = x
x = current_spot + (radius * 2)

This code is a framework for a graphics program intended to draw a “worm” made up of a series of circles. The worm is composed of NUM_CIRCLES circles, alternating in red and green colors, and is centered vertically on the canvas. The program ensures that the worm spans the entire canvas width, even if the number of circles (NUM_CIRCLES) changes.

However, the code is incomplete as it misses the necessary imports and setup for a graphics library (like tkinter in Python, or a similar library in another programming language). Also, functions like get_width(), get_height(), and add() are not defined in the provided snippet. These functions are typically part of a graphics library.

Below is a Python version of the code using tkinter, a standard GUI library in Python. This code will create a window and draw the worm as specified:

import tkinter as tk

# Constants
NUM_CIRCLES = 15
CANVAS_WIDTH = 600
CANVAS_HEIGHT = 200

def draw_worm(canvas):
    radius = CANVAS_WIDTH / NUM_CIRCLES / 2
    x = radius
    for i in range(NUM_CIRCLES):
        color = "red" if i % 2 == 0 else "green"
        canvas.create_oval(x - radius, CANVAS_HEIGHT / 2 - radius,
                           x + radius, CANVAS_HEIGHT / 2 + radius, fill=color)
        x += radius * 2

# Create the main window
root = tk.Tk()
root.title("Worm")

# Create a canvas
canvas = tk.Canvas(root, width=CANVAS_WIDTH, height=CANVAS_HEIGHT)
canvas.pack()

# Draw the worm
draw_worm(canvas)

# Start the GUI event loop
root.mainloop()

To run this code, you need to have Python installed with the tkinter library (which is included in standard Python distributions). This program will create a window displaying the worm as per the specified requirements.