Conditional Statements

Conditional statements allow your program to make decisions and execute different code based on conditions.

If Statement

Execute code only when a condition is true:

if age >= 18
    output "You are an adult"

Natural Language Comparisons

Common Pseudocode supports both symbolic and natural language comparisons:

if currentNumber equals 5
    output "The number is 5"

if currentNumber is equal to 5
    output "The number is 5"

if currentNumber == 5
    output "The number is 5"

All three forms are equivalent!

If-Else Statement

Execute one block if the condition is true, another if false:

if age >= 18
    output "You are an adult"
else
    output "You are a minor"

Else If Statement

Check multiple conditions in sequence:

if score >= 90
    output "Grade: A"
else if score >= 80
    output "Grade: B"
else if score >= 70
    output "Grade: C"
else if score >= 60
    output "Grade: D"
else
    output "Grade: F"

Note: You can also use elif or elseif instead of else if.

Comparison Operators

Greater Than and Less Than

if temperature is greater than 30
    output "It's hot!"

if temperature > 30
    output "It's hot!"

if price is less than or equal to 50
    output "Affordable!"

if price <= 50
    output "Affordable!"

Not Equal

if status does not equal "complete"
    output "Still in progress"

if status is not equal to "complete"
    output "Still in progress"

if status != "complete"
    output "Still in progress"

Logical Operators

AND - All conditions must be true

if age >= 18 AND age < 65
    output "Working age adult"

if age >= 18 and age < 65
    output "Working age adult"

if age >= 18 && age < 65
    output "Working age adult"

OR - At least one condition must be true

if day equals "Saturday" OR day equals "Sunday"
    output "It's the weekend!"

if day equals "Saturday" or day equals "Sunday"
    output "It's the weekend!"

if day equals "Saturday" || day equals "Sunday"
    output "It's the weekend!"

NOT - Invert a boolean

if NOT isLoggedIn
    output "Please log in"

if not isLoggedIn
    output "Please log in"

if !isLoggedIn
    output "Please log in"

Switch Statement

Test a value against multiple cases:

output "Enter an option (1-6 or 9): "
input userOption

switch userOption
    case 1
        output "Booking a ticket"
        jump
    case 2
        output "Canceling a ticket"
        jump
    case 3
        output "Viewing a ticket"
        jump
    case 4
        output "Viewing all tickets"
        jump
    case 5
        output "Tracking train"
        jump
    case 6
        output "Tracking all trains"
        jump
    case 9
        output "Exiting..."
        exit
    default
        output "Invalid option"

Switch Statement Notes

• Use jump or break to exit the switch after a case
• Use exit, stop, or return to terminate the program
• The default case runs if no other case matches
• Unlike some languages, cases don’t “fall through” by default

Nested Conditionals

You can nest if statements inside each other:

if hasAccount
    if isVerified
        output "Welcome back!"
    else
        output "Please verify your email"
else
    output "Please create an account"

Complex Conditions

Combine multiple logical operators:

if (age >= 18 AND age < 65) OR isStudent
    output "Eligible for standard rate"

if temperature < 0 OR temperature > 100
    output "Extreme temperature warning!"

if NOT (status equals "pending" OR status equals "processing")
    output "Order is complete or cancelled"

Tip: Use parentheses to make complex conditions clearer!