def fact(n):
f=1
for num in range(1,n 1):
if num==0:
return 1
else:
f=f*num
print(num,f)
n=int(input())
fact(n)
#here is my code, but the output should be
0 0
1 1
2 2
3 6
4 24
5 120
6 720
instead of
1 1
2 2
3 6
4 24
5 120
6 720
Can you tell me what is wrong and what should I add to the code?
CodePudding user response:
0, 0 can't really be part of the factorial because then all following numbers would have to be multiplied by 0, making them all zero. I guess you could just print it out first.
def fact(n):
f=1
print(0, 0)
for num in range(1,n 1):
f=f*num
print(num,f)
n=int(input())
fact(n)
CodePudding user response:
range
should start from0
, hencerange(0, n 1)
or justrange(n 1)
because in your code the condition is never hit- when the condition is hit you should have a
print
:print(0, 0)
def fact(n):
f=1
for num in range(0,n 1):
if num==0:
print(num, num) # num is just 0
return 1
else:
f=f*num
print(num,f)
Remarks:
- the
return
is really needed? it is always1
independently fromn
- 0! = 1 by definition. Maybe
print(0, 1)
?
CodePudding user response:
Taking for granted that 0! = 1 and 1! = 1, then you already have the two first numbers of your sequence. So you can multiply by num 1
to avoid multiplying by zero. Then you take your output before doing the next multiplication.
def fact(n):
f=1
for num in range(n 1):
print(num,f)
f=f*(num 1)
fact(5)
0 1
1 1
2 2
3 6
4 24
5 120
You can also create a lookup table if you want:
def fact(n):
FACT=[]
f=1
for num in range(n 1):
FACT = [f]
f=f*(num 1)
return FACT
F = fact(n)
F[0]
>>> 1
F[4]
>>> 24