# Basic print usage
print("Hello, World!")
print("Welcome to Python programming!")

# Printing variables
name = "Alice"
age = 25
print(name)
print(age)

# Printing multiple items
print("Name:", name, "Age:", age)
print("The answer is", 42)

# Using different separators
print("apple", "banana", "cherry", sep=", ")  # apple, banana, cherry
print("2024", "12", "25", sep="-")            # 2024-12-25
print("Loading", ".", ".", ".", sep="")       # Loading...

# Controlling the end character
print("Processing", end="...")
print("Done!")  # ProcessingDone!

print("Line 1", end="\n")
print("Line 2")  # Normal newline behavior

# Printing to different outputs (advanced)
import sys
print("Error message", file=sys.stderr)
print("Normal output", file=sys.stdout)

# Basic input
name = input("What is your name? ")
print("Hello,", name)

# Input always returns a string
age_str = input("How old are you? ")
print("Type of age_str:", type(age_str))  # <class 'str'>

# Converting input to numbers
age = int(input("Enter your age: "))
height = float(input("Enter your height in feet: "))

print(f"You are {age} years old and {height} feet tall.")

# Handling input conversion safely
try:
    number = int(input("Enter a number: "))
    print(f"Your number squared is {number ** 2}")
except ValueError:
    print("That wasn&apos;t a valid number!")

# Multiple inputs on one line
full_name = input("Enter your first and last name: ")
first, last = full_name.split()
print(f"First: {first}, Last: {last}")

# Getting multiple values
print("Enter three numbers separated by spaces:")
numbers = input().split()
num1, num2, num3 = map(int, numbers)
print(f"Sum: {num1 + num2 + num3}")

# F-string formatting (Python 3.6+)
name = "Bob"
score = 95.5
percentage = 0.875

print(f"Student: {name}")
print(f"Score: {score}")
print(f"Percentage: {percentage:.1%}")  # 87.5%

# Formatting numbers
price = 29.99
quantity = 3
total = price * quantity

print(f"Item price: ${price:.2f}")
print(f"Quantity: {quantity}")
print(f"Total: ${total:.2f}")

# Alignment and padding
items = ["Apple", "Banana", "Cherry"]
prices = [1.20, 0.50, 2.30]

print("ITEM        PRICE")
print("-" * 15)
for item, price in zip(items, prices):
    print(f"{item:<10} ${price:>5.2f}")

# Using .format() method
template = "Hello, {}! You scored {} out of {}."
message = template.format("Alice", 18, 20)
print(message)

# Named placeholders
info = "Name: {name}, Grade: {grade}".format(name="Charlie", grade="A")
print(info)

# Older % formatting (still sometimes used)
print("Hello, %s! You are %d years old." % ("David", 30))

# Simple calculator
print("=== Simple Calculator ===")
num1 = float(input("Enter first number: "))
operator = input("Enter operator (+, -, *, /): ")
num2 = float(input("Enter second number: "))

if operator == "+":
    result = num1 + num2
elif operator == "-":
    result = num1 - num2
elif operator == "*":
    result = num1 * num2
elif operator == "/":
    if num2 != 0:
        result = num1 / num2
    else:
        print("Error: Cannot divide by zero!")
        result = None
else:
    print("Error: Invalid operator!")
    result = None

if result is not None:
    print(f"Result: {num1} {operator} {num2} = {result}")

# User registration form
print("\n=== User Registration ===")
print("Please fill out the following information:")

first_name = input("First Name: ")
last_name = input("Last Name: ")
email = input("Email: ")
age = int(input("Age: "))

print("\n--- Registration Summary ---")
print(f"Name: {first_name} {last_name}")
print(f"Email: {email}")
print(f"Age: {age}")

confirm = input("\nIs this information correct? (yes/no): ")
if confirm.lower() in ["yes", "y"]:
    print("Registration completed successfully!")
else:
    print("Registration cancelled.")

# Quiz program
print("\n=== Python Quiz ===")
score = 0
total_questions = 3

print("Question 1: What is the result of 5 + 3?")
answer1 = input("Your answer: ")
if answer1 == "8":
    print("Correct!")
    score += 1
else:
    print("Incorrect. The answer is 8.")

print("\nQuestion 2: What data type is 'Hello'?")
answer2 = input("Your answer: ")
if answer2.lower() == "string" or answer2.lower() == "str":
    print("Correct!")
    score += 1
else:
    print("Incorrect. The answer is string (or str).")

print("\nQuestion 3: What is 10 / 3 in Python?")
answer3 = input("Your answer: ")
if answer3.startswith("3.33"):
    print("Correct!")
    score += 1
else:
    print("Incorrect. The answer is approximately 3.333...")

print(f"\n--- Quiz Results ---")
print(f"You scored {score} out of {total_questions}")
percentage = (score / total_questions) * 100
print(f"Percentage: {percentage:.1f}%")

# Example of best practices
def get_positive_number(prompt):
    """Get a positive number from user with validation."""
    while True:
        try:
            value = float(input(prompt))
            if value > 0:
                return value
            else:
                print("Please enter a positive number.")
        except ValueError:
            print("Please enter a valid number.")

def get_yes_no(prompt):
    """Get a yes/no response from user."""
    while True:
        response = input(prompt).lower().strip()
        if response in ["yes", "y", "1", "true"]:
            return True
        elif response in ["no", "n", "0", "false"]:
            return False
        else:
            print("Please enter yes or no.")

# Using the helper functions
print("=== Loan Calculator ===")
principal = get_positive_number("Enter loan amount: $")
rate = get_positive_number("Enter interest rate (%): ") / 100
years = get_positive_number("Enter loan term (years): ")

monthly_rate = rate / 12
num_payments = years * 12
monthly_payment = principal * (monthly_rate * (1 + monthly_rate)**num_payments) / ((1 + monthly_rate)**num_payments - 1)

print(f"\n--- Loan Details ---")
print(f"Loan Amount: ${principal:,.2f}")
print(f"Interest Rate: {rate:.2%}")
print(f"Term: {years:.0f} years")
print(f"Monthly Payment: ${monthly_payment:,.2f}")

show_schedule = get_yes_no("Show payment schedule? (yes/no): ")
if show_schedule:
    print("\nPayment schedule feature coming soon!")
else:
    print("Thank you for using the loan calculator!")