Control Flow in Dart

What is Control Flow?

• Control Flow in programming refers to the order in which individual statements, instructions or function calls are executed or evaluated.
• Loops and conditional statements help control which code runs and how many times it runs.

Conditional Statements

• Conditional Statements are instructions that let your program to make decisions based on certain conditions.
• The code runs only when the condition evaluates to true.

if Statement

• The if statement is used to execute a block of code if a specified condition is true.

void main() {
  int number = 10;

  if (number > 0) {
    print('$number is a positive number.');
  }
}

if-else Statement

• The if-else statement is used to execute one block of code if a condition is true, and another block if the condition is false.

void main() {
  int number = -5;

  if (number > 0) {
    print('$number is a positive number.');
  } else {
    print('$number is not a positive number.');
  }
}

else if Statement

• The else if statement is used to specify a new condition to test, if the first condition is false.

void main() {
  int number = 0;

  if (number > 0) {
    print('$number is a positive number.');
  } else if (number < 0) {
    print('$number is a negative number.');
  } else {
    print('$number is zero.');
  }
}

Loops

• Loops are used to execute a block of code repeatedly as long as a specified condition is true.

for Loop

• The for loop is used to iterate over a range of values or a collection.

void main() {
  for (int i = 1; i <= 5; i++) {
    print('Iteration $i');
  }
}

while Loop

• The while loop is used to execute a block of code as long as a specified condition is true.

void main(){
  int count = 1;

  while (count < 5) {
    print('Count: $count');
    count++;
  }
}

do-while Loop

• The do-while loop is similar to the while loop, but it guarantees that the block of code will be executed at least once before checking the condition.

void main() {
  int count = 1;

  do {
    print('Count: $count');
    count++;
  } while (count <= 5);
}

• break and continue Statements can also be used within loops to control the flow of execution.

void main() {
  for (int i = 1; i <= 10; i++) {
    if (i == 5) {
      break; // Exit the loop when i is 5
    }
    if (i % 2 == 0) {
      continue; // Skip even numbers
    }
    print('Number: $i');
  }
}

Assert Statement

• Its a function,that takes a condition as an argument and throws an error if the condition is false and if its true, the program continues executing normally.
• Its mainly used during development to catch bugs and validate assumptions in the code.

void main() {
  int age = 25;

  // Assert that age is greater than 0
  assert(age > 0, 'Age must be a positive number.');

  print('Age is valid: $age');
}

Resources to Learn Dart