public class addAttendee {
public Account accounts;
 public Contact del;
 public List<Contact> addattendeeList {get;set;}
 public List<Contact> delattendeeList {get;set;}
 public List<Contact> attendeeList {get;set;}
 public Integer totalCount {get;set;}
 public Integer rowIndex {get;set;}

 public List<Contact> delAttendees {get; set;}
 public addAttendee(ApexPages.StandardController controller) {

 accounts = (Account)controller.getRecord();
 attendeeList = [Select id, firstName, LastName, Email, Phone from Contact where AccountId =: accounts.Id];
 totalCount = attendeeList.size();

 delattendeeList = new List<Contact>();
 delattendees = new List<Contact>();
 }

 public void addRow(){
 addattendeeList = new List<Contact>();
 attendeeList.add(new Contact(AccountId = accounts.Id));
 }

 public PageReference ave(){

 upsert attendeeList;
 delete delattendeeList;
 return (new ApexPages.StandardController(accounts)).view();
 }

 public void deleteRow(){

 rowIndex = Integer.valueOf(ApexPages.currentPage().getParameters().get('rowIndex'));
 System.debug('rowbe deleted ' + rowIndex );
 System.debug('rowm to be deleted '+attendeeList[rowIndex]);
 del = attendeeList.remove(rowIndex);
 delattendeeList.add(del);

 }
 }

<apex:page standardController="Account" extensions="addAttendee" sidebar="false">
 <apex:form >
 <apex:pageBlock title="Accounts" id="pb">
 <apex:pageMessages />
 <apex:variable var="rowNumber" value="{!0}"/>
 <apex:pageblockSection columns="1">
 <apex:pageBlockTable title="Contacts" var="acc" value="{!attendeeList}">

 <apex:column headerValue="No." style="width:20px; text-align:center;" headerClass="centertext">
 <apex:outputText value="{0}" style="text-align:center;">
 <apex:param value="{!rowNumber+1}" />
 </apex:outputText>
 </apex:column>
 <apex:column headerValue="First Name" >
 <apex:inputField value="{!acc.FirstName}"/>
 </apex:column>
 <apex:column headerValue="Last Name" >
 <apex:inputField value="{!acc.LastName}"/>
 </apex:column>
 <apex:column headerValue="Phone" >
 <apex:inputField value="{!acc.Phone}"/>
 </apex:column>
 <apex:column headerValue="Email" >
 <apex:inputField value="{!acc.Email}"/>
 </apex:column>
 <apex:column headerValue="Action" >
 <apex:commandButton value="Delete" action="{!deleteRow}" reRender="pb">
 <apex:param name="rowIndex" value="{!rowNumber}"/>
 </apex:commandButton>
 <apex:variable var="rowNumber" value="{!rowNumber+1}"/>
 </apex:column>
 </apex:pageBlockTable>
 <apex:commandButton action="{!addRow}" value="Add Attendee" reRender="pb"/>
 </apex:pageblockSection>
 <apex:pageBlockButtons >
 <apex:commandButton value="Save" action="{!ave}" />
 <apex:commandButton value="Cancel" action="{!cancel}"/>
 </apex:pageBlockButtons>
 </apex:pageBlock>
 </apex:form>
 </apex:page>