C # [], list, array, arraylist differences and Applications

[] Is for a specific type and fixed length.

List is for a specific type and any length.

Array is of any type and fixed length.

Arraylist is for any type and length.

Array and arraylist implement any type by storing objects, so they must be converted during use.

Application Example

Using system; using system. collections. generic; using system. LINQ; using system. web; using system. web. ui; using system. web. UI. webcontrols; using system. collections; public partial class _ default: system. web. UI. page {protected void page_load (Object sender, eventargs e) {// system. int32 is the int [] arr = new int [] {1, 2, 3}; response. write (ARR [0]); // 1 change (ARR); response. write (ARR [0]); // 2 // The life of the List The namespace is system. collections. generic list <int> List = new list <int> (); list. add (1); list. add (2); list. add (3); response. write (list [0]); // 1 change (list); response. write (list [0]); // 2 // The namespace of array is system array = array. createinstance (system. type. getType ("system. int32 "), 3); // array is an abstract class and cannot be created using new array. Array. setvalue (1, 0); array. setvalue (2, 1); array. setvalue (3, 2); response. write (array. getvalue (0); // 1 change (array); response. write (array. getvalue (0); // 2 // The namespace of arraylist is system. collections arraylist = new arraylist (3); arraylist. add (1); arraylist. add (2); arraylist. add (3); response. write (arraylist [0]); // 1 change (arraylist); response. write (arraylist [0]); // 2} private void change (INT [] ARR) {for (INT I = 0; I <arr. length; I ++) {arr [I] * = 2 ;}} private void change (list <int> List) {for (INT I = 0; I <list. count; I ++) // use count {list [I] * = 2 ;}} private void change (array) {for (INT I = 0; I <array. length; I ++) // use length {array. setvalue (INT) array. getvalue (I) * 2, I); // type conversion required} private void change (arraylist) {for (INT I = 0; I <arraylist. count; I ++) // use count {arraylist [I] = (INT) arraylist [I] * 2; // type conversion required }}}