this is my vf page which show to values parent and their child which i created using fieldset
i want if user edit the values of field of parent or child then it should be updated
also i created controller if user add new child it is insert properly
but i how to update the values of child and parents


this is output of my page:



Controller:
public with sharing class AccExtension {
    Account acc;
    Public Contact Con{get;set;}
        
    public AccExtension(ApexPages.StandardController controller){
        this.acc = (Account)controller.getRecord();
        con = new Contact();
        }
    
    public List<Schema.FieldSetMember> getfieldCon(){
        list<Schema.FieldSetMember> fsFieldsList = new list<Schema.FieldSetMember>();
        fsFieldsList = SObjectType.Contact.FieldSets.Contact_Info.getFields();
        return fsFieldsList;
    }
    
    
    public PageReference save(){
        update acc;
        con.AccountId = acc.Id;
        insert con;
        return null;
    }
}

Visual force page
<apex:page standardController="Account" extensions="AccExtension" >
    <apex:form >
        <apex:pageBlock >
            <apex:pageBlockSection title="Account information" >
              <apex:repeat value="{!$ObjectType.Account.FieldSets.AccountInfo}" var="f">
                  <apex:inputField value="{!Account[f]}"/>
                </apex:repeat>
                <apex:inlineEditSupport />
            </apex:pageBlockSection>
            <apex:pageBlockSection columns="2" title="Contact Information" >
                <apex:repeat value="{!Account.contacts}" var="c">
                    <apex:repeat value="{!$ObjectType.Contact.FieldSets.Contact_Info}" var="f">
                        <apex:inputField value="{!c[f]}"/>
                    </apex:repeat>
                    <br/>
                </apex:repeat>
             </apex:pageBlockSection>
            <apex:pageBlockSection title="Create Contact">
                <apex:repeat value="{!fieldCon}" var="c">
                        <apex:inputField value="{!Con[c]}"/>
                 </apex:repeat>   
            </apex:pageBlockSection>
            <apex:commandButton action="{!Save}" value="Save" />
        </apex:pageBlock>
    </apex:form>
</apex:page>