demonstrate_conditional_statements()
# Uncomment to run interactive examples
# grade_calculator()
# simple_calculator()
Lab 4: Iterative and Control Transfer Statements
Duration: 2 Hours
Objective
Understand iterative statements (for, while loops)
Learn control transfer statements (break, continue, pass)
Theory
Iterative statements allow repetition of code blocks, while control transfer statements modify the flow of
execution within loops.
Complete Lab 4 Program
python
#!/usr/bin/env python3
"""
Lab 4: Iterative and Control Transfer Statements
Demonstrating loops and control flow statements
"""
def demonstrate_for_loops():
print("=== FOR LOOP DEMONSTRATIONS ===\n")
# Basic for loop with range
print("1. BASIC FOR LOOP WITH RANGE:")
print("Numbers from 1 to 5:")
for i in range(1, 6):
print(f" {i}")
# For loop with step
print("\n2. FOR LOOP WITH STEP:")
print("Even numbers from 0 to 10:")
for i in range(0, 11, 2):
print(f" {i}")
# For loop with list
print("\n3. FOR LOOP WITH LIST:")
fruits = ["apple", "banana", "orange", "grape"]
print("Fruits:")
for fruit in fruits:
print(f" {fruit}")
# For loop with enumerate
print("\n4. FOR LOOP WITH ENUMERATE:")
colors = ["red", "green", "blue"]
for index, color in enumerate(colors):
print(f" {index}: {color}")
# Nested for loops
print("\n5. NESTED FOR LOOPS:")
print("Multiplication table (1-3):")
for i in range(1, 4):
for j in range(1, 4):
print(f" {i} x {j} = {i * j}")
print() # Empty line for separation
def demonstrate_while_loops():
print("=== WHILE LOOP DEMONSTRATIONS ===\n")
# Basic while loop
print("1. BASIC WHILE LOOP:")
count = 1
print("Counting to 5:")
while count <= 5:
print(f" Count: {count}")
count += 1
# While loop with condition
print("\n2. WHILE LOOP WITH CONDITION:")
number = 1
print("Powers of 2 less than 100:")
while number < 100:
print(f" {number}")
number *= 2
# While loop with user input
print("\n3. WHILE LOOP FOR INPUT VALIDATION:")
print("Simulating password entry (password: 'python'):")
attempts = 0
max_attempts = 3
correct_password = "python"
# Simulated inputs for demonstration
test_inputs = ["abc", "123", "python"]
input_index = 0
while attempts < max_attempts:
if input_index < len(test_inputs):
password = test_inputs[input_index]
print(f" Attempt {attempts + 1}: Entered '{password}'")
input_index += 1
else:
break
if password == correct_password:
print(" Access granted!")
break
else:
attempts += 1
print(f" Wrong password. {max_attempts - attempts} attempts remaining.")
if attempts == max_attempts:
print(" Account locked!")
def demonstrate_control_transfer():
print("\n=== CONTROL TRANSFER STATEMENTS ===\n")
# Break statement
print("1. BREAK STATEMENT:")
print("Finding first number divisible by 7:")
for num in range(1, 20):
if num % 7 == 0:
print(f" Found: {num}")
break
print(f" Checking: {num}")
# Continue statement
print("\n2. CONTINUE STATEMENT:")
print("Printing odd numbers from 1 to 10:")
for num in range(1, 11):
if num % 2 == 0: # Skip even numbers
continue
print(f" {num}")
# Pass statement
print("\n3. PASS STATEMENT:")
print("Demonstration of pass statement:")
for i in range(5):
if i == 2:
pass # Placeholder - do nothing
else:
print(f" Processing: {i}")
# Break in nested loops
print("\n4. BREAK IN NESTED LOOPS:")
print("Searching for 15 in a 2D pattern:")
found = False
for i in range(1, 6):
for j in range(1, 6):
product = i * j
print(f" {i} x {j} = {product}")
if product == 15:
print(" Found 15! Breaking out of loops.")
found = True
break
if found:
break
# Continue in nested loops
print("\n5. CONTINUE IN NESTED LOOPS:")
print("Skipping multiples of 3:")
for i in range(1, 4):
print(f" Outer loop: {i}")
for j in range(1, 6):
if j % 3 == 0:
continue
print(f" Inner loop: {j}")
def practical_examples():
print("\n=== PRACTICAL EXAMPLES ===\n")
# Example 1: Sum of natural numbers
print("1. SUM OF NATURAL NUMBERS:")
n = 10
total = 0
for i in range(1, n + 1):
total += i
print(f" Sum of first {n} natural numbers: {total}")
# Example 2: Factorial calculation
print("\n2. FACTORIAL CALCULATION:")
n=5
factorial = 1
for i in range(1, n + 1):
factorial *= i
print(f" {n}! = {factorial}")
# Example 3: Prime number checker
print("\n3. PRIME NUMBER CHECKER:")
number = 17
is_prime = True
if number < 2:
is_prime = False
else:
for i in range(2, int(number ** 0.5) + 1):
if number % i == 0:
is_prime = False
break
print(f" {number} is {'prime' if is_prime else 'not prime'}")
# Example 4: Fibonacci sequence
print("\n4. FIBONACCI SEQUENCE:")
n_terms = 8
a, b = 0, 1
print(f" First {n_terms} Fibonacci numbers:")
for i in range(n_terms):
if i == 0:
print(f" {a}")
elif i == 1:
print(f" {b}")
else:
next_term = a + b
print(f" {next_term}")
a, b = b, next_term
# Example 5: Reverse a number
print("\n5. REVERSE A NUMBER:")
number = 12345
reversed_num = 0
temp = number
while temp > 0:
digit = temp % 10
reversed_num = reversed_num * 10 + digit
temp //= 10
print(f" Original: {number}")
print(f" Reversed: {reversed_num}")
def menu_driven_example():
print("\n=== MENU-DRIVEN CALCULATOR ===")
# Simulated menu selections for demonstration
menu_choices = ['1', '2', '3', '4']
choice_index = 0
while choice_index < len(menu_choices):
print("\n Calculator Menu:")
print(" 1. Addition")
print(" 2. Subtraction")
print(" 3. Multiplication")
print(" 4. Exit")
if choice_index < len(menu_choices):
choice = menu_choices[choice_index]
print(f" Selected: {choice}")
choice_index += 1
else:
break
if choice == '4':
print(" Exiting calculator...")
break
elif choice in ['1', '2', '3']:
a, b = 10, 5 # Sample values
print(f" Using sample values: a = {a}, b = {b}")
if choice == '1':
result = a + b
print(f" {a} + {b} = {result}")
elif choice == '2':
result = a - b
print(f" {a} - {b} = {result}")
elif choice == '3':
result = a * b
print(f" {a} * {b} = {result}")
else:
print(" Invalid choice!")
if __name__ == "__main__":
demonstrate_for_loops()
demonstrate_while_loops()
demonstrate_control_transfer()
practical_examples()
menu_driven_example()
Lab 5: Pattern Printing and String Access
Duration: 2 Hours
Objective
Learn to print various patterns using loops
Understand string indexing and slicing operations
Complete Lab 5 Program
python
