What is Singleton Pattern

Question

Would like to know what is Signleton pattern. Where it is used and why we use it.

Tejaswini Prashant J · Answer

In Singleton pattern, we create a single instance of the class and use it thru out the application , through a single global point of access . As the instance we are using thru out the appln, that is lways static. Chk this code class Singleton { // Variable public int x= 0; // Fields private static Singleton instance; // Empty Constructor protected Singleton() {} // Methods public static Singleton Instance() { if( instance == null ) instance = new Singleton(); return instance; } } protected void Page_Load(object sender, EventArgs e) { // here we are creating the instance using singleton class // Constructor is protected // Prevented from using 'new' keyword Singleton s1 = Singleton.Instance(); Singleton s2 = Singleton.Instance(); if( s1 == s2 ) Response.Write( "s1 & s2 are the same instance" ); // how we can use the class variables s1.x= 100; Response.Write(" br > s1.x=" + s1.x); s2.x= 200; Response.Write(" br > s2.x=" + s2.x); // Updates to x are updating same instance Response.Write(" br > s1.x=" + s1.x); } Hope this will help u :)

What is Singleton Pattern

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