What is the difference between a standard and a custom controller in Salesforce Apex?

Hi Arun,

Standard Controller:-

Standard controller in apex, inherits all the standard object properties and standard button functionality directly.
It contain the same functionality and logic that are used for standard Salesforce pages we can not modify it.

Custom Controller:-

It is an Apex class that implements all of the logic for a page with Custom functionality.
Custom Controllers are associated with Visualforce pages through the controller attribute.
Custom controller defines its own functionality whatever the User wants and we can modify it according to requirements.

Hi Arun

Standard controller : it is to used to use the standard functionality provided by salesforce on Visualforce page.

<apex:page standardController="Account">

</apex:page>

Custom Controller:  when we want to add our own logic to design the page with apex then we use custom controller.

<apex:page Controller="MyCustomAccount">

</apex:page>

Note: We can both standard and custom controller to use the fuctionality bu sing extensions.