I'm trying to make a factoring program, but it doesn't seem to work with negative number a-, b- and c-inputs.
from fractions import gcd
factor = -1
opp = 0
number = 1
success = 0
a = int(input("a-value: "))
b = int(input("b-value: "))
c = int(input("c-value: "))
factors = []
d = 0
e = 0
while number <= abs(a*c):
#Checking for multiples
if abs(a*c) % number == 0:
factor += 1
factors.append(number)
number += 1
while (factor-opp) >= 0:
#Checking for actual factors
d = int(factors[factor])
e = int(factors[opp])
if (abs(d+e) or abs(d-e)) == abs(b):
success += 1
break
else:
factor -= 1
opp += 1
if success > 0:
if (d+e) == b:
e = e
elif (d-e) == b:
e -= 2*e
elif (e-d) == b:
d -= 2*d
elif (-d-e) == b:
d -= 2*d
e -= 2*e
#Figuring out the equation
if d % a == 0:
d /= a
f = 1
else:
f = a/gcd(d,a)
d /= gcd(d,a)
if e % a == 0:
e /= a
g = 1
else:
g = a/gcd(e,a)
e /= gcd(e,a)
#Displaying the answer
if d >= 0:
d = str("+" + str(int(d)))
if e >= 0:
e = str("+" + str(int(e)))
elif e < 0:
e = str(int(e))
else:
d = str(int(d))
if e >= 0:
e = str("+" + str(int(e)))
elif e < 0:
e = str(int(e))
if f == 1:
if g == 1:
print ("(x" + d + ")(x" + e + ")")
else:
g = str(int(g))
print ("(x" + d + ")(" + g + "x" + e + ")")
elif g == 1:
f = str(int(f))
print ("(" + f + "x" + d + ")(x" + e + ")")
else:
f = str(int(f))
g = str(int(g))
print ("(" + f + "x" + d + ")(" + g + "x" + e + ")")
else:
print("This equation cannot be factored into integers.")
More specifically, the problem is somewhere within this block, I think. I've tested it out with print statements:
while (factor-opp) >= 0:
#Checking for actual factors
d = int(factors[factor])
e = int(factors[opp])
if (abs(d+e) or abs(d-e)) == abs(b):
success += 1
break
else:
factor -= 1
opp += 1
I've searched everywhere: my programming textbook, online searches about inputting negatives, everything. What am I doing wrong here?
Ok I am able to reproduce your issue for a simple testcase like - a=1 , b=0, c=-4 .
The issue is in the line -
if (abs(d+e) or abs(d-e)) == abs(b):
This does not check whether abs(b) is equal to abs(d+e) or abs(d-e) , instead it first evaluates the result of (abs(d+e) or abs(d-e)) , which would return the first non-zero result , and then compare that against abs(b) , so for negative numbers this does not evaluate the result correctly. Change that condition to -
if abs(d+e) == abs(b) or abs(d-e) == abs(b):
or you can also use a set -
if abs(b) in {abs(d+e), abs(d-e)}: #Though I doubt if using set would give any performance improvement because of the overhead of creating a set.
Demo after changes -
a-value: 1
b-value: 0
c-value: -4
(x+2)(x-2)
a-value: 1
b-value: -1
c-value: -6
(x-3)(x+2)
One more thing, there is something you have not considered , when a=-1 , b=-4 , c=-4 , the result should come to -(x+2)(x+2) , but the current program results in (x+2)(x+2) .