Background

Object Oriented Programming Languages allow various features to add additionally functionality to existing classes.

 

Tooling

Here are some of the available faculties:-

1. Inheritance
2. Interfaces

 

Base Class

String Class

Methods

Depending on the programming object certain methods may be exposed.

Methods such as:-

1. Length
2. Upper
3. Lower
4. Split
5. Word Count
6. Proper Case
7. Reverse
8. Convert
   • Convert to another datatype
9. Contains
   • Contains Unicode Characters

 

Method – Word Count

Outline

A trivial need is to count the number of words in a sentence.

One can tokenize the sentence based on whitespaces and count the number of tokens.

Method – wordCount

 static int wordCount
             (
                   String item
                 , Char   delimiter
             )
  {
      
    int iWordCount = -1;  
    string[] strItemArray = null;
    
     //split item
     if (
              ( item != null)
           && ( delimiter != null)
        )   
     {
         
        // using delimiter split word 
        strItemArray = item.Split
                        (
                            delimiter
                        ); 
                
        //get number of words
        iWordCount = strItemArray.Length;
        
     }
    
    return (iWordCount);
      
  } // method wordCount
  

 

Usage – Method – wordCount

To use our method, we will pass the string and our delimiter.

 String strItem;
 char   chDelimiter;
 int    iNumberofWords = -1;

 strItem = "Jack and Jill are friends of ours";
 chDelimeter = ' ';
 
 iNumberofWords = wordCount 
                   ( 
                        strItem
                      , chDelimiter 
                   );          

 

Extension Method – Word Count

Biases

Enough jerking for code on StackOverflow and one will see posters recommend refactoring the code as an Extension Method.

Requirements

Here are the requirements for extension methods:-

1. class
   • static class
2. method
   • static method
3. Method Arguments
   • first argument
     • this keyword
     • object type
     • object name

Extension Method – Our definition

1. class
   • static class
     • sample
       • public static class stringExtensions
2. method
   • static method
     • sample
       • public static int wordCount 
3. Method Arguments
   • first argument definition
     • this keyword
     • object type
     • object name
   • first argument sample
     • this string strItem

 

Extension Method – Code

namespace nsStringExtensions
{
    
    public static class stringExtensions
    {
        public static int wordCount
        (
              this string strItem
            , char delimiter = ' '
        )
        {  
             
            int iNumberofWords =-1;
            string[] strItemArray = null;
            
            if (
                       ( strItem != null)
                    && ( delimiter != null )
               )
            {
                
                 //split item
                 strItemArray = strItem.Split(delimiter); 
                
                 //get number of words
                 iNumberofWords = strItemArray.Length;
                 
            }
            
            return (iNumberofWords);
        
        } // method - wordCount
        
    } //class stringExtensions

} //namespace - nsStringExtensions

 

Usage – ExtensionMethod – wordCount

To use our method, we will directly invoke the method against our object.

 String strItem;
 char   chDelimiter;
 int    iNumberofWords = -1;

 strItem = "Jack and Jill are friends of ours";
 chDelimeter = ' ';
 
 iNumberofWords = strItem.wordCount 
                   ( 
                       chDelimiter 
                   );          

 

Source Code Control

1. GitLab
   • String – Number of Words Using Extension Method
     Link
2. GitHub
   • DanielAdeniji/stringNumberofWordsUsingExtensionMethod.cs
     Link

Online Code

1. OnlineGDB
   • wordCountLyricInCSharp
     Link

 

References

1. Wikipedia
   • Extension Method
     Link
2. Dart
   • Extension Methods
     Link