Q.Write a program that contains user defined functions to calculate area, perimeter or surface area whichever is applicable for various shapes like square, rectangle, triangle, circle and cylinder. The user defined functions should accept the values for calculation as parameters and the calculated value should be returned. Import the module and use the appropriate functions.

Put all the shape functions in a module file shapes.py, then import shapes in the main program and call the functions with parameters; each function returns its result.

# shapes.py
"""Area / perimeter / surface-area functions for common shapes."""
import math

def area_square(side):            return side * side
def perimeter_square(side):       return 4 * side
def area_rectangle(l, b):         return l * b
def perimeter_rectangle(l, b):    return 2 * (l + b)
def area_triangle(base, height):  return 0.5 * base * height
def perimeter_triangle(a, b, c):  return a + b + c
def area_circle(r):               return math.pi * r * r
def circumference_circle(r):      return 2 * math.pi * r
def surface_area_cylinder(r, h):  return 2 * math.pi * r * (r + h)

# main.py
import shapes
print("Square  (5)      :", shapes.area_square(5), shapes.perimeter_square(5)) …

The idea. When several related functions will be reused across programs, we place them in our own module — a .py file — and import it. Every function here takes the values needed for the calculation as parameters and returns the result (it does not print), which keeps the functions reusable.

Step 1 — the module (save as shapes.py):

# shapes.py
"""Area, perimeter and surface-area functions for common shapes."""
import math

def area_square(side):
    return side * side

def perimeter_square(side):
    return 4 * side

def area_rectangle(length, breadth):
    return length * breadth

def perimeter_rectangle(length, breadth):
    return 2 * (length + breadth)

def area_triangle(base, height):
    return 0.5 * base * height

def perimeter_triangle(a, b, c):
    return a + b + c

def area_circle(radius):
    return math.pi * radius * radius

def circumference_circle(radius):
    return 2 * math.pi * radius

def surface_area_cylinder(radius, height):
    # total surface area = 2*pi*r*(r + h)
    return 2 * math.pi * radius * (radius + height)

Step 2 — the main program (save as main.py in the same folder):

import shapes

print("Square side 5      -> area:", shapes.area_square(5),
      " perimeter:", shapes.perimeter_square(5))
print("Rectangle 4 x 6    -> area:", shapes.area_rectangle(4, 6),
      " perimeter:", shapes.perimeter_rectangle(4, 6))
print("Triangle b=6, h=4  -> area:", shapes.area_triangle(6, 4),
      " perimeter(3,4,5):", shapes.perimeter_triangle(3, 4, 5))
print("Circle r=7         -> area:", round(shapes.area_circle(7), 2),
      " circumference:", round(shapes.circumference_circle(7), 2))
print("Cylinder r=3, h=5  -> surface area:",
      round(shapes.surface_area_cylinder(3, 5), 2))
``` …