Dart - Comments

In every programming language comments play an important role for a better understanding of the code in the future or by any other programmer. Comments are a set of statements that are not meant to be executed by the compiler. They provide proper documentation of the code. 

Types of Dart Comments

• Dart Single Line Comment.
• Dart Multiline Comment.
• Dart Documentation Comment.

1. Dart Single-line Comment

A Dart single-line comment is used to comment a line until a line break occurs. It is done using a double forward slash (//). 

// This is a single line comment. 

Example: 

int main() 
{ 
    double area = 3.14 * 4 * 4; 
    
    // It prints the area
    // of a circle of radius = 4 
    print(area); 

    return 0; 
} 

Output:

50.24

2. Dart Multi-Line Comment

Dart Multiline comment is used to comment out a whole section of code. It uses '/*' and '*/' to start and end a multi-line comment respectively. 

/* 
These are 
multiple line 
of comments 
*/ 

Example: 

int main() 
{ 
    var lst = [1, 2, 3]; 
    
    /* 
        It prints 
        the whole list 
        at once 
    */ 
    print(lst); 
  
    return 0; 
    
} 

Output: 

[1, 2, 3]

3. Dart Documentation Comment

Dart Documentation Comments are a special type of comment used to provide references to packages, software, or projects. Dart supports two types of documentation comments "///"(C# Style) and "/**.....*/"(JavaDoc Style). It is preferred to use "///" for doc comments as many times * is used to mark list items in a bulleted list which makes it difficult to read the comments. Doc comments are recommended for writing public APIs. 

/// This is 
/// a documentation 
/// comment 

Example: 

bool checkEven(n)
{ 
      /// Returns true
      /// if n is even 
      if(n%2==0) 
          return true; 
      
      /// Returns false if n is odd 
      else 
          return false; 
} 


int main()
{ 
    
      int n = 43; 
      print(checkEven(n)); 
      return 0; 
} 

Output: 

false

Using clear comments enhances code quality, helps in debugging, and promotes better collaboration among developers. Well-structured documentation comments are especially important when creating libraries, APIs, or large-scale applications, ensuring clarity and consistency.