If Statements

Learn how to use if statements for conditional logic in Dart

Overview

If statements allow you to execute code conditionally based on boolean expressions. Dart supports simple if statements, if-else statements, and nested conditionals.

Basic Syntax

The basic structure of an if statement in Dart:

if (condition) {
  // Code executes if condition is TRUE
} else {
  // Code executes if condition is FALSE
}

If-Else Statement

An if-else statement provides two execution paths based on a condition:

int calificacion = 81;

if (calificacion >= 60) {
  print('\nAcredito\n');
} else {
  print('\nNo acredito\n');
}
// Output: Acredito

The condition must evaluate to a boolean value (true or false). Dart does not allow non-boolean values in conditional expressions.

Simple If Statement

You can use an if statement without an else clause when you only need to execute code when a condition is true:

int calificacion = 81;

if (calificacion >= 60 && calificacion <= 80) {
  print('\nAlumno regular\n');
}

Use logical operators like && (AND) and || (OR) to combine multiple conditions in a single if statement.

Nested If Statements

You can nest if statements to handle multiple conditions:

int calificacion = 81;

if (calificacion >= 90) {
  print('Excelente');
} else if (calificacion >= 80) {
  print('Muy bien');
} else if (calificacion >= 70) {
  print('Bien');
} else {
  print('Necesita mejorar');
}
// Output: Muy bien

Complete Example

Here’s a complete example demonstrating different types of if statements:

void main() {
  int calificacion = 81;

  // Type conversion demonstration
  String asd = calificacion.toString();
  int valor = int.parse(asd);
  print(valor);

  // If-else statement
  if (calificacion >= 60) {
    print('\nAcredito\n');
  } else {
    print('\nNo acredito\n');
  }

  // Simple if with compound condition
  if (calificacion >= 60 && calificacion <= 80) {
    print('\nAlumno regular\n');
  }

  // Nested if-else statements
  if (calificacion >= 90) {
    print('Excelente');
  } else if (calificacion >= 80) {
    print('Muy bien');
  } else if (calificacion >= 70) {
    print('Bien');
  } else {
    print('Necesita mejorar');
  }
}

Best Practices

1. Use else-if for readability

   Instead of deeply nested if statements, use else if chains for better code readability.

2. Keep conditions simple

   Break complex conditions into separate boolean variables with descriptive names.

3. Consider switch statements

   For multiple discrete values, consider using switch statements instead of long if-else chains.

Common Operators

Operator	Description	Example
==	Equal to	x == 5
!=	Not equal to	x != 5
>	Greater than	x > 5
<	Less than	x < 5
>=	Greater than or equal	x >= 5
<=	Less than or equal	x <= 5
&&	Logical AND	x > 0 && x < 10
`		`	Logical OR	`x < 0		x > 10`
!	Logical NOT	!(x == 5)