Lesson 5: Conditional Statements and Loops | Coding Class Series

Introduction

Welcome to Lesson 5!
In this lesson, we will learn how to make decisions in your code using conditional statements (if, elif, else) and how to repeat tasks efficiently using loops (for and while).

Conditional Statements

Conditional statements let your program execute code based on certain conditions.

Syntax in Python:

age = 18

if age >= 18:
    print("You are an adult.")
else:
    print("You are not an adult.")

Explanation:

• if age >= 18: → checks if the condition is True
• else: → executes if the condition is False

Example with multiple conditions:

marks = 75

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

Loops

Loops allow repeating code multiple times without rewriting it.

For Loop

Used to iterate over sequences like lists, strings, or ranges.

for i in range(1, 6):
    print(f"Number: {i}")

Output:

Number: 1
Number: 2
Number: 3
Number: 4
Number: 5

While Loop

Executes code as long as a condition is True.

count = 1
while count <= 5:
    print(f"Count: {count}")
    count += 1

Output:

Count: 1
Count: 2
Count: 3
Count: 4
Count: 5

Practice Exercises

1. Write a program to check if a number is positive, negative, or zero using if-elif-else.
2. Print all even numbers from 1 to 50 using a for loop.
3. Use a while loop to print the first 10 Fibonacci numbers.
4. Write a program to count the number of vowels in a string using a loop.

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Lesson 3: Conditional Statements and Loops | Coding Class Series

Welcome to Lesson 3 of our Coding Class Series! In this lesson, we will learn how to make decisions in code using conditional statements and how to repeat tasks using loops. These are essential concepts in every programming language.

Conditional Statements (if-else)

Conditional statements help your program make decisions based on certain conditions.

# Example in Python
age = 18
if age >= 18:
    print("You are an adult")
else:
    print("You are a minor")

Explanation:

• If the condition age >= 18 is True, the first block of code executes.
• If it is False, the code inside else executes.

Loops

Loops are used to repeat a block of code multiple times.

For Loop

# Print numbers from 0 to 4
for i in range(5):
    print(i)

While Loop

count = 0
while count < 5:
    print(count)
    count += 1

Practice Exercises

1. Write a program to check if a number is even or odd.
2. Print numbers from 1 to 10 using a loop.
3. Create a loop that sums all numbers from 1 to 100.
4. Write a program to print only the numbers divisible by 3 between 1 and 50.