please send the sample code for  delete,sendmail,update button code for this visualforce page controler when the check box is checked

<apex:page Controller="con2" >
<apex:form >
<apex:pageMessages />
<apex:pageBlock title="Book data to Store" mode="edit">
 
 
 <!--This is the first section-->
<apex:pageBlockSection Title="Book Information" columns="1">

<apex:pageBlockSectionItem >
<apex:outputText value="BookName"/>
<apex:inputtext value="{!bk.Name}"/>
</apex:pageBlockSectionItem>
<apex:pageBlockSectionItem >
<apex:outputText value="Authorname"/>
<apex:inputText value="{!bk.Authorname__c}"/>
</apex:pageBlockSectionItem>
<apex:pageBlockSectionItem >
<apex:outputText value="price"/>
<apex:inputText value="{!bk.price__c}"/>
</apex:pageBlockSectionItem>
<apex:pageBlockSectionItem >
<apex:outputText value="EmailId"/>
<apex:inputText value="{!bk.Emailid__c}"/>
</apex:pageBlockSectionItem>
 </apex:pageblocksection>
 
 <apex:pageBlockButtons location="top">
   
    <apex:commandButton value="save" action="{!save}" />
    <apex:commandButton value="Reset" action="{!Reset}" />
    
  </apex:pageBlockButtons>
  <apex:pageBlockButtons location="bottom">
   <apex:commandButton value="Delete" action="{!delete_selected}" />
    <apex:commandButton value="update" />
    <!-- action="{!Edit}" /-->
    <apex:commandButton value="sendmail"/ >          
    <!-- action="{!sendMail}"/-->
  </apex:pageBlockButtons>
 
 <apex:pageBlockTable value="{!bks}" var="b" >
 <apex:column headerValue="Action">
 <apex:inputCheckbox value="{!b.action__c}" />
 </apex:column>
      <apex:column value="{!b.Authorname__c}"/>
       <apex:column value="{!b.Name}"/>
       <apex:column value="{!b.price__c}"/>
       <apex:column value="{!b.Emailid__c}"/>
      </apex:pageBlockTable>

</apex:pageBlock>
</apex:form>
</apex:page>