How to update case owner using apex???

Hi Everybody,
       I want to fetch the records based on the topic name ..
For Example
I have 15 contacts ..10 contacts are associated with the topic name sample1 and others are sample2

Wanna fetch the records associated with the topic name sample1

Please Help!

<apex:pageBlock ><apex:pageblockSection ><apex:pageBlockSectionItem >
                     <apex:inputText styleClass="form-control" id="email" value="{!email}" style="width:400px"/>
                     <!--<apex:inputText styleClass="input-medium" id="email" value="{!email}"/>-->
                     <apex:commandButton value="Confirm" styleClass="btn-primary" action="{!UpdateCart}" style="background:orange"/>
                     <!-- <input type="email" class="form-control" id="exampleInputEmail1"> </input>-->
                     </apex:pageBlockSectionItem></apex:pageblockSection></apex:pageBlock>

 I want a textbox and commandbutton on same line. How to achive this without using <apex:pageblock>?
Please help!!
 

Hi folks,
           Can anyone tell me how to use topics in visualforce page?
Please give some example 



Thanks in advance
Karthick