Question

Try to debug it! (fixes needed are explained below)
########################################
##def primes_list_buggy(n):
## """
## input: n an integer > 1
## returns: list of all the primes up to and including n
## """
## # initialize primes list
## if i == 2:
## primes.append(2)
## # go through each elem of primes list
## for i in range(len(primes)):
## # go through each of 2...n
## for j in range(len(n)):
## # check if not divisible by elem of list
## if i%j != 0:
## primes.append(i)
#
#
## FIXES: --------------------------
## = invalid syntax, variable i unknown, variable primes unknown
## can't apply 'len' to an int
## division by zero -> iterate through elems not indices
## -> iterate from 2 not 0
## forgot to return
## primes is empty list for n > 2
## n = 3 goes through loop once -> range to n+1 not n
## infinite loop -> append j not i
## -> list is getting modified as iterating over it!
## -> switch loops around
## n = 4 adds 4 -> need way to stop going once found a divisible num
## -> use a flag
## --------------------------
def primes_list_buggy(n):
"""
## input: n an integer > 1
## returns: list of all the primes up to and including n
## """
# initialize primes list
if i == 2:
primes.append(2)
# go through each elem of primes list
for i in range(len(primes)):
# go through each of 2...n
for j in range(len(n)):
# check if not divisible by elem of list
if i%j != 0:
primes.append(i)

print(primes_list(2) )   
print(primes_list(15) )

(a) Debug the program by using Python Programming Language.

Answer 1

PYTHON CODE

def primes_list(n):
        
        # initialize primes list
        primes = []
        
        # go through each elem of primes list
        for i in range(2, n+1):
                #flag is used
                flag = 0
                # go through each of 2...i-1
                for j in range(2,i):
                    # check if divisible by elem of list
                    if i%j == 0:
                        #if it is divisible then change flag as 1
                        flag = 1
                        break
                if flag == 0:#if flag as 0, then append element in primes list
                    primes.append(i)
                        
        return primes

print(primes_list(2) )
print(primes_list(15) )

PYTHON CODE SCREENSHOT

OUTPUT SCREENSHOT