Programming Paradigms Introduction

Approaches to programming: Procedural vs. Object-Oriented

Procedural: Step-by-step instructions using blocks of code (loops, logic statements, functions) to execute the program.
Object-oriented: Using objects to store data and do calculations.

Problem: Perimeter of Triangle

Write a program to calculate the perimeter of a triangle given the coordinates of the three verticies.

The distance between two points is: $d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}$

Write this program yourself before looking at the approaches below.

Notes and Code	Outcome
Procedural: Basic	Show Notes ▼ `# INPUT p1_x = 4 p1_y = 3 p2_x = -4 p2_y = 7 p3_x = -5 p3_y = -4 # CALCULATIONS # distance between (1) and (2) side1 = ((p2_x - p1_x)2 + (p2_y - p1_y)2)0.5 # distance between (2) and (3) side2 = ((p3_x - p2_x)2 + (p3_y - p2_y)2)0.5 # distance between (3) and (1) side3 = ((p1_x - p3_x)2 + (p1_y - p3_y)2)*0.5 # Perimeter = total distance perimeter = side1 + side2 + side3 # OUTPUT print("Perimeter: ", perimeter)` perimeter-p.py* Output: Show Notes ▼
Procedural: Using a distance function	Show Notes ▼ `# FUNCTIONS def distance(x1, y1, x2, y2): d = ((x2-x1)2 + (y2-y1)2)*0.5 return d # INPUT p1_x = 4 p1_y = 3 p2_x = -4 p2_y = 7 p3_x = -5 p3_y = -4 # CALCULATIONS # distance between (1) and (2) side1 = distance(p1_x, p1_y, p2_x, p2_y) # distance between (2) and (3) side2 = distance(p2_x, p2_y, p3_x, p3_y) # distance between (3) and (1) side3 = distance(p3_x, p3_y, p1_x, p1_y) # Perimeter = total distance perimeter = side1 + side2 + side3 # OUTPUT print("Perimeter: ", perimeter)` perimeter-p.py* Output: Show Notes ▼
Object Oriented: Using a point class Uses a point class with a distanceTo method that calculates the distance to another point.	Show Notes ▼ # CLASSES class point: def __init__(self, x, y): self.x = x self.y = y # Method to find the distance to another point (p) def distanceTo(self, p): d = ((self.x-p.x)2 + (self.y-p.y)2)*0.5 return d # INPUT p1 = point(4,3) p2 = point(-4,7) p3 = point(-5,-4) # CALCULATIONS # distance between (1) and (2) side1 = p1.distanceTo(p2) # distance between (2) and (3) side2 = p2.distanceTo(p3) # distance between (3) and (1) side3 = p3.distanceTo(p1) # Perimeter = total distance perimeter = side1 + side2 + side3 # OUTPUT print("Perimeter: ", perimeter) perimeter-oo.py* Output: Show Notes ▼
Object Oriented: Using a point class and a triangle class Uses a point class with a distanceTo method that calculates the distance to another point and a triangle class that calculates the perimeter.	Show Notes ▼ # CLASSES class point: def __init__(self, x, y): self.x = x self.y = y # Method to find the distance to another point (p) def distanceTo(self, p): d = ((self.x-p.x)2 + (self.y-p.y)2)*0.5 return d # Triangle class that takes three vertices as point class instances. class triangle: def __init__(self, p1, p2, p3): self.p1 = p1 self.p2 = p2 self.p3 = p3 def perimeter(self): p = self.p1.distanceTo(self.p2) p += self.p2.distanceTo(self.p3) p += self.p3.distanceTo(self.p1) return p # INPUT p1 = point(4,3) p2 = point(-4,7) p3 = point(-5,-4) tri = triangle(p1, p2, p3) # CALCULATIONS perimeter = tri.perimeter() # OUTPUT print("Perimeter: ", perimeter) perimeter-oo.py* Output: Show Notes ▼
Assignment: Area of a triangle Write a program to calculate the area of the triangle. You can use Heron's formula to determine the area of a triangle based on the lengths of its sides, or there is a formula you can use based on the vertices of triangle.	Output: Show Notes ▼ If you did not use an object-oriented approach, try this problem again doing so.
Assignment: Find the perimeter of a polygon. Find the perimeter of the polygon. Explain which method you used and why. The distance between two points is: $d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}$	Output: Show Notes ▼ If you did not use an object-oriented approach, try this problem again doing so.
Assignment: Find the Area of a polygon. Find the area of the polygon. A convex polygon can be broken down into triangles.	Output: Show Notes ▼ If you did not use an object-oriented approach, try this problem again doing so.

Notes and Code

Outcome

Procedural: Basic

Show Notes ▼

# INPUT
p1_x = 4
p1_y = 3
p2_x = -4
p2_y = 7
p3_x = -5
p3_y = -4

# CALCULATIONS
# distance between (1) and (2)
side1 = ((p2_x - p1_x)**2 + (p2_y - p1_y)**2)**0.5

# distance between (2) and (3)
side2 = ((p3_x - p2_x)**2 + (p3_y - p2_y)**2)**0.5

# distance between (3) and (1)
side3 = ((p1_x - p3_x)**2 + (p1_y - p3_y)**2)**0.5

# Perimeter = total distance
perimeter = side1 + side2 + side3


# OUTPUT
print("Perimeter: ", perimeter)

perimeter-p.py

Output:

Show Notes ▼

Perimeter:  31.3913871781778

Procedural: Using a distance function

Show Notes ▼

# FUNCTIONS
def distance(x1, y1, x2, y2):
    d = ((x2-x1)**2 + (y2-y1)**2)**0.5
    return d

# INPUT
p1_x = 4
p1_y = 3
p2_x = -4
p2_y = 7
p3_x = -5
p3_y = -4

# CALCULATIONS
# distance between (1) and (2)
side1 = distance(p1_x, p1_y, p2_x, p2_y)

# distance between (2) and (3)
side2 = distance(p2_x, p2_y, p3_x, p3_y)

# distance between (3) and (1)
side3 = distance(p3_x, p3_y, p1_x, p1_y)

# Perimeter = total distance
perimeter = side1 + side2 + side3


# OUTPUT
print("Perimeter: ", perimeter)

perimeter-p.py

Output:

Show Notes ▼

Perimeter:  31.3913871781778

Object Oriented: Using a point class

Uses a point class with a distanceTo method that calculates the distance to another point.

Show Notes ▼

# CLASSES
class point:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    # Method to find the distance to another point (p)
    def distanceTo(self, p):
        d = ((self.x-p.x)**2 + (self.y-p.y)**2)**0.5
        return d

# INPUT
p1 = point(4,3)
p2 = point(-4,7)
p3 = point(-5,-4)

# CALCULATIONS
# distance between (1) and (2)
side1 = p1.distanceTo(p2)

# distance between (2) and (3)
side2 = p2.distanceTo(p3)

# distance between (3) and (1)
side3 = p3.distanceTo(p1)

# Perimeter = total distance
perimeter = side1 + side2 + side3


# OUTPUT
print("Perimeter: ", perimeter)

perimeter-oo.py

Output:

Show Notes ▼

Perimeter:  31.3913871781778

Object Oriented: Using a point class and a triangle class

Uses a point class with a distanceTo method that calculates the distance to another point and a triangle class that calculates the perimeter.

Show Notes ▼

# CLASSES
class point:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    # Method to find the distance to another point (p)
    def distanceTo(self, p):
        d = ((self.x-p.x)**2 + (self.y-p.y)**2)**0.5
        return d

# Triangle class that takes three vertices as point class instances.
class triangle:
    def __init__(self, p1, p2, p3):
        self.p1 = p1
        self.p2 = p2
        self.p3 = p3

    def perimeter(self):
        p = self.p1.distanceTo(self.p2)
        p += self.p2.distanceTo(self.p3)
        p += self.p3.distanceTo(self.p1)
        return p

# INPUT
p1 = point(4,3)
p2 = point(-4,7)
p3 = point(-5,-4)

tri = triangle(p1, p2, p3)

# CALCULATIONS
perimeter = tri.perimeter()

# OUTPUT
print("Perimeter: ", perimeter)

perimeter-oo.py

Output:

Show Notes ▼

Area:  31.3913871781778

Assignment: Area of a triangle

Write a program to calculate the area of the triangle.

You can use Heron's formula to determine the area of a triangle based on the lengths of its sides, or there is a formula you can use based on the vertices of triangle.

Output:

Show Notes ▼

Perimeter:  46.000

If you did not use an object-oriented approach, try this problem again doing so.

Assignment: Find the perimeter of a polygon.

Find the perimeter of the polygon. Explain which method you used and why.

The distance between two points is: $d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}$

Output:

Show Notes ▼

Perimeter:  47.17423524981518

If you did not use an object-oriented approach, try this problem again doing so.

Assignment: Find the Area of a polygon.

Find the area of the polygon. A convex polygon can be broken down into triangles.

Output:

Show Notes ▼

Area:  140

If you did not use an object-oriented approach, try this problem again doing so.