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Control Flow

Minilux provides conditional statements and loops for controlling program flow.

if / elseif / else​

Basic if Statement​

if ($age >= 18) {
    printf("You are an adult")
}

if-else​

if ($score >= 60) {
    printf("Passed!")
} else {
    printf("Failed")
}

if-elseif-else​

if ($score >= 90) {
    printf("Grade: A")
} elseif ($score >= 80) {
    printf("Grade: B")
} elseif ($score >= 70) {
    printf("Grade: C")
} elseif ($score >= 60) {
    printf("Grade: D")
} else {
    printf("Grade: F")
}

Compound Conditions​

Important: When using AND or OR in conditions, use double parentheses:

# ✅ CORRECT - Double parentheses for compound conditions
if (($age >= 18) AND ($hasID == 1)) {
    printf("Access granted")
}

if (($isWeekend == 1) OR ($isHoliday == 1)) {
    printf("Day off!")
}

# ✅ CORRECT - Simple conditions use single parentheses
if ($age >= 18) {
    printf("Adult")
}

Nested if Statements​

if ($age >= 18) {
    if ($hasLicense == 1) {
        printf("You can drive")
    } else {
        printf("You need a license")
    }
} else {
    printf("Too young to drive")
}

while Loop​

Execute code repeatedly while a condition is true:

Basic Loop​

$i = 1
while ($i <= 5) {
    printf("Count: ", $i)
    inc $i + 1
}

Output:

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

Countdown Loop​

$countdown = 10
while ($countdown > 0) {
    printf($countdown, "...")
    dec $countdown - 1
}
printf("Blast off!")

Loop with Compound Condition​

$counter = 0
$max = 100

while (($counter < $max) AND ($counter < 10)) {
    printf("Counter: ", $counter)
    inc $counter + 1
}

Infinite Loop Prevention​

Always ensure your loop condition will eventually become false:

# ❌ WARNING: Infinite loop!
$x = 1
while ($x > 0) {
    printf("This will never stop!")
    # Forgot to modify $x
}

# ✅ CORRECT: Loop will terminate
$x = 10
while ($x > 0) {
    printf("x = ", $x)
    dec $x - 1  # Modify the loop variable
}

Pattern Examples​

Factorial Calculation​

$n = 5
$result = 1

while ($n > 0) {
    $result = $result * $n
    dec $n - 1
}

printf("Factorial: ", $result)  # prints 120

Sum of Numbers​

$i = 1
$sum = 0

while ($i <= 10) {
    $sum = $sum + $i
    inc $i + 1
}

printf("Sum of 1 to 10: ", $sum)  # prints 55

Array Iteration​

$fruits = ["apple", "banana", "orange"]
$i = 0

while ($i < len($fruits)) {
    printf("Fruit ", $i, ": ", $fruits[$i])
    inc $i + 1
}

Finding Maximum​

$numbers = [5, 12, 3, 99, 42, 7]
$max = $numbers[0]
$i = 1

while ($i < len($numbers)) {
    if ($numbers[$i] > $max) {
        $max = $numbers[$i]
    }
    inc $i + 1
}

printf("Maximum value: ", $max)  # prints 99

Control Flow Best Practices​

  1. Always modify loop variables to avoid infinite loops
  2. Use double parentheses with AND/OR operators
  3. Keep conditions simple when possible
  4. Indent code blocks for better readability
  5. Comment complex logic to explain your intentions
# Good example with comments
$score = 85

# Check if student passed with honors
if (($score >= 90) AND ($attendance >= 90)) {
    printf("Passed with honors")
} elseif ($score >= 70) {
    printf("Passed")
} else {
    printf("Need to improve")
}