Why with an input of 4 the product would be 24?

Question

product = 1
end_value = int(input("Enter a number: "))
for i in range(1, end_value+1)        
    product = product * I
    i += 1
print("The product is ", product)

Can someone explain how with an input of 4 the product is 24?

Answer 1

Your question is "Why with an input of 4 the product would be 24?"

Because 1 * 2 * 3 * 4 = 24

However, that's not what your code is doing. You have an unknown variable I (typo?) and you are incrementing i again inside your for-loop.

Change I back to i and remove i += 1

Answer 2

There are many mistakes in your code. For loops are used for iterating over data structures, so there is no need to increment i, like i += 1, inside a for loop.

product = 1
end_value = int(input("Enter a number: "))
for i in range(1, end_value+1):
    product = product * i
print("The product is ", product)

When end_value = 4

First Iteration:

product = 1
i = 1
product = product * i ===> (product = 1*1)

now value of product is 1. This is passed onto next iteration.

Second Iteration:

product = 1
i = 2
product = product * i ===> (product = 1*2)

now value of product is 2. This is passed onto next iteration.

Third Iteration:

product = 2
i = 3
product = product * i ===> (product = 2*3)

now value of product is 6. This is passed onto next iteration.

Fourth Iteration:

product = 6
i = 4
product = product * i ===> (product = 6*4)

now value of product is 24. After the fourth iteration, the for loop stops and the value of product is printed as 24.

Output

Enter a number: 4
The product is 24