[Tutor] Program to find if a number entered by user is a prime number or not

[Manprit Singh]

Dear sir,
If i simply write this program as given below:

x = int(input("Enter any positive number"))
a = "not prime"
if all(x%i for i in range(2, int(x**0.5) + 1)):
    if x >= 2:
        a = "prime"
print(x,"is",a)

Will it be ok ?

On Fri, Oct 16, 2020 at 7:00 AM Manprit Singh <manpritsinghece at gmail.com>
wrote:

> Dear Sir ,
>
> I was trying to write a program which allows the user to input a number
> from a keyboard , it then prints the message x is prime if number input by
> user is a prime number and x is not prime if the number input by user is
> not a prime number. (here x represents the number). The program is written
> below:
>
> x = int(input("Enter any positive number"))
> a = "not prime"
> if all(x%i for i in range(2, int(x**0.5) + 1)):
>     if x < 2:
>         pass
>     else:
>         a = "prime"
> else:
>     pass
> print(x,"is",a)
>
> I have these questions in my mind :
> 1) If you can see I have used pass two times , Initially I have assigned a
> string "not prime" to variable a . Now if user input is either 0 or 1 , it
> is not a prime number. That's why i have written a pass inside the below
> written block, which will  maintain a = 'not prime" when user input is
> either 0 or 1.
>
> if all(x%i for i in range(2, int(x**0.5) + 1)):
>     if x < 2:
>         pass
> for any value of user input greater than 1 if the iterable inside all( )
> is empty or all(x%i for i in range(2, int(x**0.5) + 1)) return True , the
> user input for sure is a prime number , and hence i have assigned a =
> "prime" inside that block.
>
> Again for the second time i have used pass when all(x%i for i in range(2,
> int(x**0.5) + 1)) returns False, in that case the number input by user is
> again not a prime number , and hence i have used pass again in the block to
> maintain the old value of variable a ="not prime".
>
> Just need to know if my way of implementing the problem is correct ? Can
> this program be further optimised ?
>
> Regards
> Manprit Singh
>
>
>
>