Structure of a program in Python

The structure of a program is defined by its control flow. It is built from blocks of code, where each block has a single entry and a single exit point in the control flow.
The typical structure of a python program include 3 parts

Import statements
// import statements are used to include library files to the python program

Function definitions
//This section include the definitions of various functions written in a Python Program

Program statements
// This section include the set of statements for solving the given problem.

Example:

#import module statement
import math

#function definition statements
def findarea(r):
    area=math.pi * r * r
    print("Area of circle is : " , area)

#programming statements
r=int(input("enter radius of circle"))
findarea(r)

Output is:

enter radius of circle7
Area of circle is :  153.93804002589985