1. Create a Custom Field No_Of_Contats on Account Object 2. When ever new Contact is created or deleted update the no_of_contacts fields with no of contacts that exits for the parent records

1. Create a Custom Field No_Of_Contats on Account Object 

2. When ever new Contact is created  or deleted update the 
 no_of_contacts fields with no of contacts that exits for the parent records


trigger contactsTriggers on Contact (after insert,after delete) {
    if(Trigger.isInsert && Trigger.isAfter)
        TriggerContact.increment(Trigger.New);
    else
        TriggerContact.increment(Trigger.Old);

}


public class TriggerContact {
    public static void increment(List<Contact> cons){
        set<Id> accid=new Set<id>();
        for(Contact c:cons){
           accId.add(c.AccountId); 
        }
       List<Account> accs=[select id,No_of_contacts__c ,(select id from Contacts ) from Account where id in:accId];
        for(Account a:accs){
            a.no_of_contacts__c=a.contacts.size();
        }
        update accs;
    }

}