Question

In python please

4. Write the code that will define a function that takes any given random number as input and it will check to see if that number given from the input is a prime number or not. (if you forgot what prime is from algebra, look it up)

Answer 1

Python Code: (Python 3 implementation)

def primeCheck():
n = int(input('Enter a number: '))

flag = 1
for i in range(2, n):
if(n%i == 0):
flag = 0

if(flag == 0):
print('{} is not a prime number.'.format(n))
else:
print('{} is a prime number.'.format(n))

primeCheck()

1 def primeCheck() 2 n-int (input ( 'Enter a number: ')) flag1 for i in range (2, n) 4 flag 0 if (flag0) 10 print('is not a prime number.".format (n)) else print is a prime number.".format (n)) 12 13 14 primeCheck)

Sample results :

Enter a number: 31 31 is a prime number.

Enter a number: 32 32 is not a prime number

Explanation:

A prime number is divisible only by 1 and the number itself.

So, if a number 'n' is divisible by any number between 1 and n(2, ... , n-1), then 'n' is not a prime number.

primeCheck() is the Python function that takes a random number as input and will print whether the given number is a prime number or not.

input('Enter a number: ') is used to take the input from the user along with a message "Enter a number: ", which returns a string datatype. To convert the string to integer datatype, we typecast it using int().

Initially, the variable flag is set to 1, which represents a prime number. If flag is 0, then the number is not a prime number.

Then, using a for loop, we iterate from 2 to n-1. If the input number 'n' is divisible by any number from 2 to n-1(remainder of the division n%i is 0), we set the flag to 0(denoting a non prime number).

Finally, after the for loop, if the value of flag variable is unchanged(flag is 1), then the number is a prime number. Else(flag is 0), then the number is not a prime number.

(If the given number is 1 (or 2), then the for loop is not executed, so the flag value remains 1, denoting that 1 (or 2) is a prime number.)