Code Explanation

The above code has the following components:

1. Function is_prime, which takes a number as a parameter and defines the function logic using if-else statements and for loop. The logic behind the code is that if a number is greater than 1 and is divisible by any number in the range [2 to number) then it is not prime. Else, it is prime. It returns a boolean value using the return keyword.

2. Variable lower_limit, which stores the user-provided number for the start of the range.

3. Variable upper_limit, which stores the user-provided number for the end of the range.

4. Error checking using the if statement: if upper_limit is less than equal to lower_limit, then print an error message stating that the values are not valid.

5. If the lower_limit is an even number, we increment it by 1 to make it odd so that we can skip even numbers. To skip the even number, we have added step=2 in the for loop.

6. for loop that loops from lower_limit to upper_limit+1 using the range() function to print primes in the range with an if-else statement and calls the is_prime function, and if the returned value is true, then prints that number on the output screen. The Optimization we did here is skipping the even numbers because even numbers except 2 are not prime. So skipping those even numbers saves us many iterations. The end parameter (end=‘ ‘) indicates that the end character must be identified by whitespace, not a new line.

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