csharp

Collections are similar to arrays: they store lists of objects. Hwever they provide a lot of usefull features not found in arrays (resizing, sorting etc). Microsoft .Net Framework provides severaltypes of collection classes_

• ArrayList Class -similar to array
  
  
  
  • Remove method - removes an element
  
  
  • Add method - adds a new element at the end
  
  
  • Insert method - inserts a new element somewhere in the middle
  
  
  
  


• Stack Class - implements LIFO mechanism - like a stack
  
  
  
  • Push - adds an element at the beginning
  
  
  • Pop - removes an element from the end
  
  
  
  


• Hashtable Class - associative array - using other data types as element key
  
  
  
  • ContainsKey - ckeck if the key is already taken
  
  
  • elements are stored in DictionaryEntry object - used in foreach loop
  
  
  
  


• SortedList Class - similar to Hashtable - elements allways sorted (by using key)

SortedList peopleAge = new SortedList();

peopleAge["john"] = 31;

peopleAge["mary"] = 36;

peopleAge["James"] = 53;

peopleAge["Francesca"] = 18;