🧭 Conditional Statements in Python | Lesson 08

🧭 Conditional Statements in Python

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Conditional statements make your program decide what to do based on different situations. They let your code be smart and choose a path depending on conditions—like a traffic light for your program’s flow! 🚦

What Are Conditional Statements? 🤔

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They allow you to execute certain blocks of code only if a specific condition is true.

1. The if Statement ✅

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Basic way to run code when a condition is true.

age = 18
if age >= 18:
    print("You are an adult.")

• The code inside the if block runs only if age >= 18 is true.

2. The if-else Statement 🔄

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Choose between two paths.

age = 16
if age >= 18:
    print("You are an adult.")
else:
    print("You are a minor.")

3. The if-elif-else Ladder 🪜

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Check multiple conditions one by one.

marks = 75
if marks >= 90:
    print("Grade: A")
elif marks >= 75:
    print("Grade: B")
elif marks >= 50:
    print("Grade: C")
else:
    print("Grade: F")

Important Tips for Conditionals

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• Conditions return True or False.
• Indentation after if, elif, and else is mandatory.
• Use comparison operators (==, !=, <, >, <=, >=) in conditions.

Practice Questions with Solutions 🏆

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1. Practice: Write a program to check if a number is positive or negative.
   • Solution:

num = int(input("Enter a number: "))
if num > 0:
    print("Positive")
elif num < 0:
    print("Negative")
else:
    print("Zero")

2. Practice: Check if a person is eligible to vote (age 18 or more).
   • Solution:

age = int(input("Enter your age: "))
if age >= 18:
    print("Eligible to vote!")
else:
    print("Not eligible yet.")

Step-by-Step Challenge: Simple Calculator 🧮

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Write a program that asks the user to enter two numbers and an operator (+, -, *, /) and then performs the operation.

num1 = float(input("Enter first number: "))
num2 = float(input("Enter second number: "))
op = input("Enter operator (+, -, *, /): ")

if op == "+":
    print(num1 + num2)
elif op == "-":
    print(num1 - num2)
elif op == "*":
    print(num1 * num2)
elif op == "/":
    if num2 != 0:
        print(num1 / num2)
    else:
        print("Error! Division by zero.")
else:
    print("Invalid operator.")

Checklist for This Chapter ✅

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• Used if for simple decisions
• Used if-else for two outcomes
• Used if-elif-else for multiple choices
• Handled conditions with comparison operators

You’re now ready to control the flow of your programs using decisions! Start building smart, interactive apps! 🚦🎉