Step 1 - Function with no parameters

void sayHello() {
  print('Hello');
}

void main() {
  sayHello();
  sayHello();
}

• void means this function does not return a value.

Step 2 - Function with parameters

void greet(String name) {
  print('Hello, $name');
}

void main() {
  greet('Shafi');
  greet('Maria');
}

• name is an input parameter.
• Function becomes reusable for different values.

Step 3 - Function with return value

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

void main() {
  int sum = add(3, 4);
  print(sum);
}

• Return type (int) should match the returned value.

Good habit

• One function should do one clear job.
• Use clear names: calculateTotal, findMax, isValidEmail.

Practice tasks

• Write int multiply(int a, int b).
• Write bool isEven(int n).
• Write String fullName(String first, String last).