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Introduction

Functions can return values to the calling code, making them more powerful and flexible. Instead of just performing actions, functions can compute and return results.

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Basic Return Syntax

To return a value from a function, specify the return type and use the return keyword: 
int operacion() {
  int valorUno = 10;
  int valorDos = 15;
  int suma = valorUno + valorDos;
  return suma;
}

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Key Components

  • Return type: int - specifies what type of value the function returns
  • return statement: Returns the computed value back to the caller
  • Local variables: Variables defined inside the function are only accessible within it

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Using Return Values

There are multiple ways to use the value returned by a function:

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Direct Print

Print the returned value directly: 
print(operacion());
// Output: 25

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Store in Variable

Capture the return value in a variable for later use: 
int resultado = operacion();
print('El Resultado de la Función es: $resultado');
// Output: El Resultado de la Función es: 25

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String Interpolation

Embed the function call directly in a string: 
print('El Resultado de la Función es: ${operacion()}');
// Output: El Resultado de la Función es: 25

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Complete Example

int operacion(){
  int valorUno = 10;
  int valorDos = 15;
  int suma = valorUno + valorDos;
  return suma;
}

void main() {
  //Una forma de uso con Retorno
  print(operacion());

  //Otra forma es:
  int resultado = operacion();
  print('El Resultado de la Función es: $resultado');

  //Otra más
  print('El Resultado de la Función es: ${operacion()}');
}

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Common Return Types

int

Returns integer numbers
int sumar(int a, int b) => a + b;

double

Returns decimal numbers
double dividir(int a, int b) => a / b;

String

Returns text values
String saludar() => 'Hola';

bool

Returns true or false
bool esMayor(int a, int b) => a > b;

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Return Statement Rules

  • A function with a return type must return a value of that type
  • The return statement immediately exits the function
  • Code after a return statement won’t be executed
  • Functions with non-void return types must have a return statement in all code paths

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Multiple Return Points

Functions can have multiple return statements based on conditions: 
String obtenerCalificacion(int puntaje) {
  if (puntaje >= 90) {
    return 'A';
  } else if (puntaje >= 80) {
    return 'B';
  } else {
    return 'C';
  }
}
When storing return values in variables, make sure the variable type matches the function’s return type, or use var to let Dart infer the type.

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Best Practices

  • Always specify the correct return type
  • Use meaningful variable names for stored return values
  • Return early to avoid deep nesting
  • Keep return logic simple and clear

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