Program to Print all the Prime Numbers within a Given Range

Python Program to Print all the Prime Numbers within a Given Range

Given the upper limit range, the task is to print all the prime numbers in the given range in Python.

Examples:

Example1:

Input:

given number = 95

Output:

The prime numbers from 2 to upper limit [ 95 ] :
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89

Example2:

Input:

given number = 52

Output:

Enter some random upper limit range = 52
The prime numbers from 2 to upper limit [ 52 ] :
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47

Python Program to Print all the Prime Numbers within a Given Range

There are several ways to print all the prime numbers from 2 to the upper limit range some of them are:

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Method #1:Using for loop(Static Input)

Approach:

  • Give the number as static input and store it in a variable.
  • Set the first for loop to have a range of 2 to the upper limit range.
  • Take a temporary variable which is the count variable and initialize it to zero.
  • Allow the second for loop to have a range of 2 to half the number (excluding 1 and the number itself).
  • Then, using the if statement, determine the number of divisors and increment the count variable each time.
  • The number is prime if the number of divisors is lower than or equal to zero.
  • Prime numbers till the given upper limit range are printed.
  • The Exit of the Program.

Below is the implementation:

# Give the number as static input and store it in a variable.
givenNumbr = 95
print('The prime numbers from 2 to upper limit [', givenNumbr, '] :')
# Set the first for loop to have a range of 2 to the upper limit range.
for valu in range(2, givenNumbr+1):
  # Take a temporary variable which is the count variable and initialize it to zero.
    cntvar = 0
    # Allow the second for loop to have a range of 2 to
    # half the number (excluding 1 and the number itself).
    for divi in range(2, valu//2+1):
      # Then, using the if statement, determine the number of divisors
      # and increment the count variable each time.
        if(valu % divi == 0):
            cntvar = cntvar+1
    # The number is prime if the number of divisors is lower than or equal to zero.
    if(cntvar <= 0):
        print(valu, end=' ')

Output:

The prime numbers from 2 to upper limit [ 95 ] :
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89

All the prime numbers till the upper limit range are printed.

Method #2:Using for loop(User Input)

Approach:

  • Give the number as user input with the help of the int(input()) function and store it in a variable.
  • Set the first for loop to have a range of 2 to the upper limit range.
  • Take a temporary variable which is the count variable and initialize it to zero.
  • Allow the second for loop to have a range of 2 to half the number (excluding 1 and the number itself).
  • Then, using the if statement, determine the number of divisors and increment the count variable each time.
  • The number is prime if the number of divisors is lower than or equal to zero.
  • Prime numbers till the given upper limit range are printed.
  • The Exit of the Program.

Below is the implementation:

# Give the number as user input with the help
# of the int(input()) function and store it in a variable.
givenNumbr = int(input('Enter some random upper limit range = '))
print('The prime numbers from 2 to upper limit [', givenNumbr, '] :')
# Set the first for loop to have a range of 2 to the upper limit range.
for valu in range(2, givenNumbr+1):
  # Take a temporary variable which is the count variable and initialize it to zero.
    cntvar = 0
    # Allow the second for loop to have a range of 2 to
    # half the number (excluding 1 and the number itself).
    for divi in range(2, valu//2+1):
      # Then, using the if statement, determine the number of divisors
      # and increment the count variable each time.
        if(valu % divi == 0):
            cntvar = cntvar+1
    # The number is prime if the number of divisors is lower than or equal to zero.
    if(cntvar <= 0):
        print(valu, end=' ')

Output:

Enter some random upper limit range = 52
The prime numbers from 2 to upper limit [ 52 ] :
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47

Explanation:

  • The user must enter the range’s upper limit and save it in a separate variable.
  • The first for loop runs until the user enters an upper limit.
  • The count variable is initially set to 0.
  • Because the for loop runs from 2 to half of the number, 1 and the number itself is not considered divisors.
  • If the remainder is equal to zero, the if statement looks for the number’s divisors.
  • The count variable counts the number of divisors, and if the count is less than or equal to zero, the integer is prime.
  • If the count exceeds zero, the integer is not prime.
  • All the prime numbers till the upper limit range are printed.

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