Question 25 - Sample Paper 1 by Teachoo - Teachoo Sample Paper

Predict the output of the following code:

def Factorial (N) :

    if N == 0 or N == 1:

        return 1

    else:

        return N * Factorial (N-1)

X = 5

Y = Factorial (X)

print(Y)

X = Factorial (X-2)

print(X, end='?')

Answer:

Answer by student

120 

6?

Detailed answer by teachoo

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• The question asks us to predict the output of the code. The code defines a function named Factorial that takes a parameter named N , which is a positive integer. The function returns the factorial of N , which is the product of all positive integers from 1 to N . The function uses recursion, which means it calls itself with a smaller argument until it reaches a base case. The base case is when N is 0 or 1, in which case the function returns 1. Otherwise, the function returns N multiplied by the factorial of N-1 .
• The code then assigns 5 to a variable named X and calls the Factorial function with X as an argument. It assigns the result to a variable named Y and prints it. To calculate the value of Y , we can use the following steps:
• Factorial (5) = 5 * Factorial (4)
• Factorial (4) = 4 * Factorial (3)
• Factorial (3) = 3 * Factorial (2)
• Factorial (2) = 2 * Factorial (1)
• Factorial (1) = 1 (base case)
• Factorial (2) = 2 * 1 = 2
• Factorial (3) = 3 * 2 = 6
• Factorial (4) = 4 * 6 = 24
• Factorial (5) = 5 * 24 = 120
• Therefore, Y is equal to 120 and it is printed on the first line of the output.
• The code then calls the Factorial function with X-2 as an argument and assigns the result to X . It prints X with a question mark at the end. To calculate the value of X , we can use the following steps:
• X-2 = 5-2 = 3
• Factorial (3) = 3 * Factorial (2)
• Factorial (2) = 2 * Factorial (1)
• Factorial (1) = 1 (base case)
• Factorial (2) = 2 * 1 = 2
• Factorial (3) = 3 * 2 = 6
• Therefore, X is equal to 6 and it is printed on the second line of the output with a question mark.

So, the output of the code is:

120

6?

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