General Beginner

Control Structures: Making Decisions in Code

Imran Nadwi

3 months ago

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Teaching Programs to Make Decisions

Control structures allow programs to make decisions and repeat actions. They're like the decision-making brain of your program!

Conditional Statements (If/Then/Else)

Conditional statements let your program choose different paths based on conditions, just like how you make decisions in real life.

Basic If Statement

age = 18

if age >= 18:
    print("You can vote!")
else:
    print("You cannot vote yet.")
    
// Real-life equivalent:
// IF you are 18 or older, THEN you can vote
// OTHERWISE, you cannot vote yet

Multiple Conditions

Sometimes you need to check multiple conditions:

Multiple If Statements

temperature = 75

if temperature > 80:
    print("It's hot! Wear shorts.")
else if temperature > 60:
    print("It's nice! Perfect weather.")
else if temperature > 40:
    print("It's cool. Bring a jacket.")
else:
    print("It's cold! Bundle up!")

Comparison Operators

These help you compare values:

== Equal to
!= Not equal to
> Greater than
< Less than
>= Greater than or equal to
<= Less than or equal to

Logical Operators

Combine multiple conditions:

AND - Both conditions must be true
OR - At least one condition must be true
NOT - Opposite of the condition

Logical Operators Example

age = 25
hasLicense = true

// Using AND
if age >= 18 AND hasLicense == true:
    print("You can drive!")
    
// Using OR
if age < 13 OR age > 65:
    print("Special ticket pricing available!")
    
// Using NOT
if NOT gameOver:
    print("Keep playing!")

Real-World Decision Making

Programs make decisions constantly:

ATM: "If PIN is correct, show account balance"
Game: "If player health is 0, game over"
Website: "If user is logged in, show dashboard"
Weather App: "If it's raining, suggest umbrella"

🎯 Decision Making Exercise

Write conditional logic for these scenarios:

A program that checks if someone can watch an R-rated movie (age 17+)
A grade calculator that assigns letter grades based on scores
A simple login system that checks username and password

Nested Conditions

You can put conditions inside other conditions:

Nested If Example

weather = "sunny"
temperature = 75

if weather == "sunny":
    if temperature > 70:
        print("Perfect day for the beach!")
    else:
        print("Sunny but a bit cool.")
else:
    print("Maybe stay inside today.")

Best Practices

Keep conditions simple and readable
Use meaningful variable names
Consider all possible cases
Test your conditions with different values