Amr Ahmed Ramadan

Jan 31, 20221 min

Program to print prime numbers from 1 to N.

#prime #from1toN #python

Given a number N, the task is to print the prime numbers from 1 to N.

Examples:

Input: N = 10
 
Output: 2, 3, 5, 7

Algorithm ( Steps):

  • First, take the number N as input.

  • Then use a for loop to iterate the numbers from 1 to N

  • Then check for each number to be a prime number. If it is a prime number, print it

Approach: Now, according to the formal definition, a number ‘n’ is prime if it is not divisible by any number other than 1 and n. In other words, a number is prime if it is not divisible by any number from 2 to n-1

Implementation:

  1. Create a function called isPrime that takes a parameter n

def isPrime(n):

2. Since 0 and 1 is not prime return false

if(n == 1 or n == 0):
 
return False

3. Run a loop from 2 to n-1, if the number is divisible by i,
 
then n is not a prime number.

for i in range(2, n):
 

 
if(n % i == 0):
 
return False

4. otherwise, n is prime number.

return True

The function is created.....

5. Take an N numbers.

N = 100

6. check for every number from 1 to N

for i in range(1, N+1):

7. check if the current number is prime and print it.

if(isPrime(i)):
 
print(i, end=" ")

Source Code:

Github
 

Code:

Output:

    0