Question

Draw a stack diagram to show how the following code is executed and write the generated output.

def sequence(n, m):
    if n < 0:
        return 1
    elif n + m > 5:
        return sequence(n, m - 1)
    else:
        return n * sequence(m - 1, n + 1)

print(sequence(5, 3))

Answer 1

Draw a stack diagram to show how the following code is executed and write the generated output:

Stack diagram:

• Main method will call sequence(5, 3).

• n + m > 5 → 8 > 5 is true.

return sequence(n, m-1) → return sequence(5, 2)

• n + m > 5 → 7 > 5 is true.

return sequence(n, m-1) → return sequence(5, 1)

• n + m > 5 → 6 > 5 is true.

return sequence(n, m-1) → return sequence(5, 0)

• n + m > 5 → 5 > 5 is false.

return n * sequence(m-1, n+1) → 5 * sequence(0-1, 5+1)

→ 5 * sequence(-1, 6) [Here, n = -1, m = 6]

→ 5 * 1

→ 5

• Return output sequence(5, 3) = 5

Provided code:

def sequence(n,m):

if n<0:

return 1

elif n + m > 5:

return sequence(n,m-1)

else:

return n * sequence(m-1,n+1)

print(sequence(5,3))

Output: 5

Output of the above code is integer value 5.