Answer
code
Work Step by Step
# 13.13 (Tkinter: display a graph) A graph consists of vertices and edges that connect
# vertices. Write a program that reads a graph from a file and displays it on a
# panel. The first line in the file contains a number that indicates the number of
# vertices (n). The vertices are labeled as 0, 1, ..., n-1. Each subsequent line, with
# the format u x y v1, v2, ..., describes that the vertex u is located at position
# (x, y) with the edges (u, v1), (u, v2), and so on. Figure 13.12a gives an example
# of the file for a graph. Your program prompts the user to enter the name of the
# file, reads data from the file, and displays the graph on a panel, as shown in
# Figure 13.12b.
from tkinter import *
def readFile():
file = open("graph.txt", "r")
data = []
n = file.readline().strip()
for i in range(int(n)):
data.append(file.readline().strip())
vertices = []
for line in data:
line = line.split()
line = [eval(x) for x in line]
vertices.append(line)
return vertices
window = Tk()
cnvs = Canvas(window)
cnvs.pack()
points = readFile()
for u in points:
x1 = u[1]
y1 = u[2]
v1 = points[u[3]]
v2 = points[u[4]]
x2 = v1[1]
y2 = v1[2]
x3 = v2[1]
y3 = v2[2]
cnvs.create_oval(x1 - 4, y1 - 4, x1 + 4, y1 + 4, fill="black")
cnvs.create_line(x1, y1, x2, y2)
cnvs.create_line(x1, y1, x3, y3)
cnvs.create_text(x1 - 8, y1 - 8, text=str(u[0]))
window.mainloop()
