my python program is to find prime numbers between two intervals but i am getting 9 in the output ca-CodePudding

python code to give prime numbers between two intervals

start = int(input('enter starting point of interval:'))
end = int(input('enter ending point of interval:'))
for i in range(start,end 1):
    if i>1:
        for j in range(2,i 1):
            if (i % j == 0):
                break
            else:
                print(i, end = " ")
                break

the output if i put start and end as 2,10 was 3,5,7,9 please tell what mistake i am doing

CodePudding user response：

In case of 9, you're checking if the number is divisible by 2, it's not, and then you print the number and don't check anything else.

You're also looping till i 1, meaning you check if the number is divisible by itself, which it is...

Try changing those:

start = int(input('enter starting point of interval:'))
end = int(input('enter ending point of interval:'))
for i in range(start,end 1):
    if i>1:
        for j in range(2,i):
            if (i % j == 0):
                break
        else:
            print(i, end = " ")

Also, instead of checking if i>1 in every loop, change the loop conditions, and you can loop until the square root.

End result:

import math
start = int(input('enter starting point of interval:'))
end = int(input('enter ending point of interval:'))
for i in range(max(start, 2),end 1):
    if i % 2 == 0  and i != 2: continue
    if all((i%j!=0) for j in range(3,int(math.sqrt(i)) 1, 2)):
        print(i, end = " ")