Dart Syntax

Syntax Overview

Dart syntax is similar to C, Java, and JavaScript. Understanding the basic syntax rules helps you write valid Dart code and avoid errors.

Statements & Expressions

A statement is a complete instruction that performs an action. Every statement in Dart ends with a semicolon (;).

int age = 25;           // declaration statement
print(age);             // expression statement
age = age + 1;          // assignment statement

An expression is a piece of code that evaluates to a value:

5 + 3          // evaluates to 8
age > 18       // evaluates to true or false
'Hello'        // evaluates to the string "Hello"

Case Sensitivity

Dart is case-sensitive. name, Name, and NAME are three different identifiers.

String name = 'Alice';
// String Name = 'Bob';  ← different variable!
print(name);  // Alice

Whitespace & Indentation

Dart ignores extra whitespace and blank lines. However, consistent indentation (2 or 4 spaces) makes code readable. The dart format tool formats code automatically.

// Both are valid but the second is more readable:
void main(){print('Hi');}

void main() {
  print('Hi');
}

Dart Keywords

Keywords are reserved words with special meaning. You cannot use them as variable names:

abstract  as        assert    async     await
break     case      catch     class     const
continue  default   do        else      enum
extends   false     final     finally   for
if        import    in        is        late
new       null      return    static    super
switch    this      throw     true      try
var       void      while     with

Full Example

void main() {
  // Variables and types
  String language = 'Dart';
  int version = 3;
  bool isAwesome = true;

  // Output with string interpolation
  print('$language version $version is awesome: $isAwesome');

  // Simple arithmetic
  int a = 10;
  int b = 3;
  print('Sum: $${a + b}');
  print('Product: $${a * b}');
}

Dart version 3 is awesome: true
Sum: 13
Product: 30

⚠️ Common Mistakes

• Forgetting the semicolon at the end of a statement.
• Using a keyword as a variable name (e.g., var class = 5;).
• Mixing up capitalization (e.g., calling Print() instead of print()).

🧠 Quiz

Summary

Dart syntax is C-style with semicolons ending statements. It is case-sensitive. Whitespace is ignored but indentation improves readability. Dart keywords are reserved and cannot be used as identifiers.