Trigger scenario2 in salesforce :

Account - Account Number -india

countrty__c - name(Text) and Checkbox__c  --

insert contact. 

While inserting Account field account number value is 'India' then compare to without related object Country__c ,and have field name value 'India' and  

Checkbox__c  ='true'

Then insert the contact. If doesn't have 

field name value 'India' and  Checkbox__c  ='true' doesn't insert the contact.

Trigger triggernameForPorton on account(after insert){

   list<contact> lstcon = new list<contact>();

   set<string> sbc = new set<string>();

   Map<string,string> mapc = new map<string,string>();

    if(trigger.isinsert && trigger.isAfter){

     for(account acc : trigger.new){

       sbc.add(acc.accountnumber);

     }

    }

    for(country__c c: [select id,name,Checkbox__c from Country__c where name IN:sbc and Checkbox__c =true ]){

        mapc.put(c.name,c.name);

    }   

   for(account acc : trigger.new){

    if(mapc.containsKey(acc.accountnumber)) {

        contact con = new contact();

        con.lastname =  acc.name;

        con.phone = '8867414079';

        con.email ='test@gmail.com';

        con.AccountId = acc.id;

        lstcon.add(con);

}

  }

    if(lstcon !=null){

        insert lstcon;

    }

}

Auto populate a  field Email "Email " on contact  with an  custom Email field "EMAIL__c" from the Account object or possibliy from Account Object itself, needs to happen when a user selects the account and saves the record.

trigger childtoparent on Contact (before update) {

    set<id> accids = new set<id>();

    for(contact con : trigger.new){

        if(con.Status__c == 'Active'){

        accids.add(con.AccountId);

        }

    }

    map<id,account> mapacc = new map<id,account>([select id,name,industry,email__c from account where id IN: accids  ]);

    for(contact con : trigger.new){

        if(mapacc.get(con.accountid).industry == 'Banking'){

        if( mapacc.containsKey(con.accountid)){

        con.email = mapacc.get(con.AccountId).email__c;

        }

    }

    }

}

Error: Invalid Data. 
Review all error messages below to correct your data.
Apex trigger childtoparent caused an unexpected exception, contact your administrator: childtoparent: execution of BeforeUpdate caused by: System.NullPointerException: Attempt to de-reference a null object: Trigger.childtoparent: line 10, column 1

trigger childtoparent on Contact (before update) {

    set<id> accids = new set<id>();

    for(contact con : trigger.new){

        if(con.Status__c == 'Active'){

        accids.add(con.AccountId);

        }

    }

    map<id,account> mapacc = new map<id,account>([select id,name,industry,email__c from account where id IN: accids and industry = 'Banking'  ]);

    for(contact con : trigger.new){

       // if(mapacc.get(con.accountid).industry == 'Banking'){

        if( mapacc.containsKey(con.accountid)){

        con.email = mapacc.get(con.AccountId).email__c;

        }

  //  }

    }

}