Python Program to print prime numbers between given range

In this simple python program, we need to display prime numbers of a range. It's a beginner-level python program.

To understand this example, you should have knowledge of the following Python programming topics:

What is a prime number?

In this python program example, we need to print all the prime numbers between two numbers given by the user. To understand the program clearly, we need to check what is mean by a prime number? A number with only 2 divisors, which are 1 and that number itself, is called a Prime number.

How we display prime numbers in a range?

So in this python example, we need to check every number in a range if it's prime or not. To achieve that, we use two for loop using the range function. The range() function is used with the for loop in python, the range() function is used to loop through a specified number of times.

Range() function in python has the default value starting from zero and increment by 1 every time and ends when it reaches a specified value. For example, if we use 'for x in range(3)' then the loop starts from zero as default and up to 2. please note the loop ends at 2, not 3.

This python program uses two for loop nested like the outer for loop starts from the lower number up to the upper range. Then inside the loop, we check for the number is greater than zero; if it is true, we start the inner for loop from range 2 to that number. Inside the inner loop, we use the Mod operator and check that is equal to zero using if condition in python; if it is equal to zero, break the loop, and it is not a prime. Else print the number as prime. Let us break the code

ALGORITHM

STEP 1: Accept the user's values for the lower and upper value using input function in python and convert into an integer using int datatype.

STEP 2: Start the outer for loop using the range from lower value to upper value +1. We use up+1 to reach the up value.

STEP 3: Add an if condition to check if the number is positive or not.

STEP 4: Start the inner for loop to check every number prime or not by using the mod operator

STEP 5: If the number is divisible by any number, break the loop. Else print the number.

Python Source Code

                                          #Take the input from the user:   
low = int(input("Enter lower range: "))  
up = int(input("Enter upper range: "))  
  
for n in range(low,up + 1):  
   if n > 1:  
       for i in range(2,n):  
           if (n % i) == 0:  
               break  
       else:  
           print(n)  
                                      

OUTPUT

Enter low range: 2
Enter up range: 10
2
3
5
7