Introduction of python

Python is a high-level and most popular programming language. it was created by Guido van Rossum, and released on February 20, 1991.

Uses of python:-

It is used for general-purpose programming like

·         Mathematics

·         System scripting

·         Software development

·         Web development

Why python?

•          Python works on different-different platforms like Windows, Mac, Linux, etc.
•          It has a simple syntax.
•          It has a syntax that allows developers to write the program with fewer lines than some other programming language.
•          It has an object-orientated way or a functional way.

What can do python?

•          It can connect to the database system and also read and modify files.
•         It is used on the server to create the server-side application.
•          It is used alongside software to create workflows.
•          It is used to handle big data and performed complex mathematics.

Syntex in python:-

The syntax is the set of rules that defines how a Python program will be written and interpreted by both runtime systems and human readers.

•       Python uses new lines to complete commands, as opposed to other programming languages which often use semicolons or parentheses.

•          It relies on indentation, using whitespace, to define the scope of the loop, function, and classes. Other programming languages often use curly-brackets for this purpose.

Example:-

print("Hello Python")

Linear Recursion in C

If a recursive function is calling itself for only once then, the recursion is linear.
Pseudocode:-

fun(int n)
{

    if (n > 0)
    {

        ...
        fun(n - 1);     // Calling itself only once

        ...
    }

}

Note: The fun() is calling itself for only once.

 
Understanding linear recursion by a simple problem
C program to find a cube of the positive number using Recursion.

#include <stdio.h>
 

int fun(int n)
{

    static int x;
    if (n > 0)

    {
        x++;

        return fun(n - 1) + x * x;
    }

}
int main()

{
    int a;

    printf("number ");
    scanf("%d", &a);

    printf("%d", fun(a));
    return 0;

}

Output:-

 Tracing the above Recursion:-

C program to find the factorial of a positive number using Recursion.

#include <stdio.h>

 

int fun(int n)

{

    if (n == 0)

    {

        return 1;

    }

    else

    {

        return fun(n - 1) * n;

    }

}

 

int main()

{

    int x;

    printf("number ");

    scanf("%d", &x);
    printf("%d\n", fun(x));

    return 0;

}

Output:-