public class EmailSending {
    public string emailAddress {get;set;}
    public string subject {get;set;}
    public string body {get;set;}
    
    public list<string> forConversition {get;set;}
    public list<contact> cts	{get;set;}
    public String rec {get;set;}
    
    public EmailSending (){
        forConversition = new List<string>();
      //  cts	=	new list<contact>();
        cts	=	[SELECT Name,ID,Email FROM Contact limit 10];
       // gg= new Group__c ();
       
    }
    
    public void sendEmail(){
      // subject	=	'the address is'+a;
       //body		=	'this is a test body that is being sent to '+a;
        //system.debug(a);
         Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();       	
       		forConversition.add(emailAddress);               
        		email.setToAddresses(forConversition);
           // System.debug('email'+emailAddress);
        	email.setSubject(subject);
        	email.setPlainTextBody( body );
        Messaging.SendEmailResult [] r = Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});  
       
    }
    public void gettoActivate(){
        system.debug('how are you guys');
        rec	=	ApexPages.CurrentPage().getParameters().get( 'varId' );
         system.debug('recid is'+rec);
       // return new pagereference(rec);
    }
    public void sendHTMLTemp(){
        //system.debug(varID);
        rec	=	ApexPages.CurrentPage().getParameters().get( 'varId' );
        system.debug(rec);
      //  cts	=	[SELECT ID from Contact where ID=:rec];
        EmailTemplate et = [SELECT Id FROM EmailTemplate where name =:'HTML temp1'];
        Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();       	
       		forConversition.add(emailAddress);               
        		email.setToAddresses(forConversition);
        		email.setTemplateId(et.Id);
        	email.setTargetObjectId(rec);
           // System.debug('email'+emailAddress);
        	//email.setSubject(subject);
        	//email.setPlainTextBody( body );
        Messaging.SendEmailResult [] r = Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});
    }
    public void sendVFTemp(){
         rec	=	ApexPages.CurrentPage().getParameters().get( 'varId' );
        system.debug(rec);
        EmailTemplate et = [SELECT Id FROM EmailTemplate where name =:'VF page e-mail Template'];
        Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();       	
       		forConversition.add(emailAddress);               
        		email.setToAddresses(forConversition);
        		email.setTemplateId(et.Id);
        	email.setTargetObjectId(rec);
           // System.debug('email'+emailAddress);
        	//email.setSubject(subject);
        	//email.setPlainTextBody( body );
        Messaging.SendEmailResult [] r = Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});
    }
    
    public void clearit(){
        emailAddress = Null;
        subject= Null;
        body= Null;
    }
}

<apex:page controller="EmailSending">
    <apex:form id="ww">    	
        <apex:pageBlock >
            <apex:pageBlockSection collapsible="false" columns="3" >
            	<apex:pageBlockTable value="{!cts}" var="c">
                	<apex:column headerValue="Name">
                        <apex:commandLink value="{!c.name}" action="{!gettoActivate}" reRender="ww">
                        <apex:param value="{!c.id}" name="varId"/>
                        </apex:commandLink>
                    </apex:column>
                    <apex:column value="{!c.id}" />
                    <apex:column value="{!c.Email}" />
                </apex:pageBlockTable>
           </apex:pageBlockSection>
            <apex:pageBlockButtons location="bottom">
                <apex:commandButton value="Send E-mail" action="{!sendEmail}" />
                <apex:commandButton value="Send VF Template" action="{!sendVFTemp}"/>
                <apex:commandButton value="Send HTML" action="{!sendHTMLTemp}" /> 
                <apex:commandButton action="{!clearit}" value="Reset" reRender="aa" />
            </apex:pageBlockButtons>            
            <apex:pageBlockSection columns="3" id="aa" >            
                <apex:inputText value="{!emailAddress}" label="Enter E-mail Address * :" required="true" />                   
                <apex:inputText value="{!subject}" label="Subject :"/>                  
                <apex:inputTextarea value="{!body}" label="Body :"/>         
            </apex:pageBlockSection>
        </apex:pageBlock>
           
    </apex:form>
</apex:page>