Chapter 5: Control Flow in Python

1. Conditional Statements (if, elif, else)

Flowchart of conditional logic

Basic Syntax

if condition1:
    # code if condition1 is True
elif condition2:
    # code if condition2 is True
else:
    # code if all conditions are False

Example: Age Check

age = 18

if age < 13:
    print("Child")
elif age < 20:
    print("Teenager")
else:
    print("Adult")

Output

Teenager

Exercise 1: Grade Calculator

Write a program that:

Takes a score input (0-100)
Prints the grade (A: 90+, B: 80-89, etc.)

score = int(input("Enter score: "))

if score >= 90:
    print("Grade: A")
elif score >= 80:
    print("Grade: B")
elif score >= 70:
    print("Grade: C")
else:
    print("Grade: F")

2. Loops

While Loops

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

For Loops

fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit.upper())

Exercise 2: Number Guessing Game

Create a game that:

Generates a random number (1-100)
Keeps prompting the user until they guess it
Gives "too high/too low" hints

import random

target = random.randint(1, 100)
while True:
    guess = int(input("Guess (1-100): "))
    if guess == target:
        print("Correct!")
        break
    elif guess < target:
        print("Too low")
    else:
        print("Too high")

3. Loop Control Statements

break

for num in range(10):
    if num == 5:
        break
    print(num)  # Stops at 4

continue

for num in range(5):
    if num == 2:
        continue
    print(num)  # Skips 2

Exercise 3: Prime Number Checker

Write a program that:

Takes a number input
Uses a loop to check if it's prime
Breaks early if divisor found

num = int(input("Enter number: "))
is_prime = True

for i in range(2, int(num**0.5) + 1):
    if num % i == 0:
        is_prime = False
        break

print(f"{num} is {'prime' if is_prime else 'not prime'}")

Chapter 5: Control Flow in Python – Conditional Statements & Loops

1. Conditional Statements (if, elif, else)

Basic Syntax

Example: Age Check

Output

Exercise 1: Grade Calculator

2. Loops

While Loops

For Loops

Exercise 2: Number Guessing Game

3. Loop Control Statements

break

continue

Exercise 3: Prime Number Checker