Control Structures

Control structures allow you to control the flow of execution in your Flexa programs. They include conditionals, loops, and flow control statements. In this section, we’ll explore how to use these structures effectively.

Conditionals

Conditionals allow you to execute different blocks of code based on certain conditions.

1. If Statement

The if statement executes a block of code if a condition is true.

if (condition) {
  // Code to execute if the condition is true
}

Example

var age = 18;

if (age >= 18) {
  println("You are an adult.");
}

2. If-Else Statement

The if-else statement allows you to execute one block of code if a condition is true and another block if it is false.

if (condition) {
  // Code to execute if the condition is true
} else {
  // Code to execute if the condition is false
}

Example

var age = 16;

if (age >= 18) {
  println("You are an adult.");
} else {
  println("You are a minor.");
}

3. Else-If Statement

The else-if statement allows you to check multiple conditions.

if (condition1) {
  // Code to execute if condition1 is true
} else if (condition2) {
  // Code to execute if condition2 is true
} else {
  // Code to execute if all conditions are false
}

Example

var score = 85;

if (score >= 90) {
  println("Grade: A");
} else if (score >= 80) {
  println("Grade: B");
} else if (score >= 70) {
  println("Grade: C");
} else {
  println("Grade: F");
}

4. Switch Statement

The switch statement allows you to execute different blocks of code based on the value of an expression.

switch (expression) {
  case value1:
    // Code to execute if expression == value1
    break;
  case value2:
    // Code to execute if expression == value2
    break;
  default:
    // Code to execute if no case matches
}

Example

var day = 3;

switch (day) {
  case 1:
    println("Monday");
    break;
  case 2:
    println("Tuesday");
    break;
  case 3:
    println("Wednesday");
    break;
  default:
    println("Invalid day");
}

Loops

Loops allow you to execute a block of code repeatedly.

1. While Loop

The while loop executes a block of code as long as a condition is true.

while (condition) {
  // Code to execute while the condition is true
}

Example

var i = 0;

while (i < 5) {
  println("i = " + i);
  i++;
}

2. Do-While Loop

The do-while loop executes a block of code at least once, then repeats as long as a condition is true.

do {
  // Code to execute at least once
} while (condition);

Example

var i = 0;

do {
  println("i = " + i);
  i++;
} while (i < 5);

3. For Loop

The for loop allows you to execute a block of code a specific number of times.

for (expression1; expression2; expression3) {
  // Code to execute in each iteration
}

Example

for (var i = 0; i < 5; i++) {
  println("i = " + i);
}

4. Foreach Loop

The foreach loop iterates over elements in a collection (e.g., arrays, strings, structs).

foreach (var element in collection) {
  // Code to execute for each element
}

Example

var numbers = {1, 2, 3, 4, 5};

foreach (var num in numbers) {
  println("Number: " + num);
}

Flow Control

Flow control statements allow you to alter the flow of execution in loops and functions.

1. Break Statement

The break statement exits a loop or switch statement immediately.

while (true) {
  if (condition) {
    break; // Exit the loop
  }
}

Example

for (var i = 0; i < 10; i++) {
  if (i == 5) {
    break; // Exit the loop when i == 5
  }
  println("i = " + i);
}

2. Continue Statement

The continue statement skips the rest of the current iteration and moves to the next iteration of the loop.

for (var i = 0; i < 10; i++) {
  if (i % 2 == 0) {
    continue; // Skip even numbers
  }
  println("i = " + i);
}

3. Return Statement

The return statement exits a function and optionally returns a value.

fun add(a: int, b: int): int {
  return a + b;
}

What’s Next?

Now that you understand control structures, it’s time to learn about functions in Flexa. Head over to the Functions section to dive deeper.

← Back to Variables and Constants Next: Functions →