Python Control Flow Statements: Review Questions

for loop:

• What is the difference between a for loop and a while loop in Python?
• Can you use a for loop to iterate over a string?

if statement:

• Can you have multiple elif blocks in an if-elif-else statement?

• What is the purpose of nesting if statements?

• Question: What is printed when mystery_loop() is called? Explain why the loop terminates early.

def mystery_loop():  
    x = 5  
    while x > 0:  
        print(x)  
        x -= 1  
        if x == 2:  
            break  
    print("Loop ended!")  

• Question: What does check_value(7) print? What happens if the order of the elif statements is reversed?

def check_value(n):  
    if n > 10:  
        print("A")  
    elif n > 5:  
        print("B")  
    elif n > 3:  
        print("C")  
    else:  
        print("D")  

• Question: What is the final output? Why does this happen? How would you fix it to remove all even numbers?

numbers = [1, 2, 3, 4]  
for num in numbers:  
    if num % 2 == 0:  
        numbers.remove(num)  
print(numbers)  

• Question: Which case is printed? Explain how operator precedence affects the outcome.

a, b, c = True, False, True  
if not a or b and c:  
    print("Case 1")  
else:  
    print("Case 2")  

• Question: Why does this loop run infinitely? How would you fix it?

def countdown(n):  
    while n > 0:  
        print(n)  
        n += 1  
    print("Blastoff!")  

• Question: This code incorrectly classifies some leap years (e.g., 2000). Identify the flaw and fix the logic.

def is_leap_year(year):  
    if year % 4 == 0:  
        return True  
    elif year % 100 == 0:  
        return False  
    elif year % 400 == 0:  
        return True  
    else:  
        return False