HI

Just remove the public key word before registrations__c in the line number 5.
public Registrations__c s=new Registrations__c();
Registrations__c s=new Registrations__c(); Make like this

Try:

public class sregdform{

public Registrations__c s {get;set;}

//In constructor

s = new Registrations__c();

}

That solve your problem.

public class sregdform
{
//public Registration__c s{get;set;}
public boolean displyvalue{get;set;}
public boolean displyform{get;set;}
Registration__c s=new Registration__c();
public sregdform()
{
//public Registration__c s{get;set;}
//s=new Registration__c();
displyvalue=true;
}
public Registration__c gets()
{
return s;
}
public void send()
{
if((s.password__c == s.confirmpassword__c) )
{
//insert s;
Database.SaveResult sr=Database.insert(s,false);
if(sr.issuccess())
{
ApexPages.Message myMsg = new ApexPages.Message(ApexPages.Severity.Confirm,'Inserted Successfully');
ApexPages.addMessage(myMsg);}
else
{
ApexPages.Message myMsg = new ApexPages.Message(ApexPages.Severity.error,'Please check the details');
ApexPages.addMessage(myMsg);
}
}
else
{
ApexPages.Message myMsg = new ApexPages.Message(ApexPages.Severity.error,'Please confirm your password');
ApexPages.addMessage(myMsg);
}
}
public void cancel()
{
s=new registration__c();
}
public void next()
{
string studentnumber = s.mobileno__c ;
if(studentNumber.length()== 14 )
{
system.debug('IF block');
displyvalue=false;
displyform=true;
}
else
{
system.debug('ELSE block');
displyvalue=true;
displyform=false;
ApexPages.Message myMsg = new ApexPages.Message(ApexPages.Severity.error,'Please enter 10 digits phone number');
ApexPages.addMessage(myMsg);
}
}
public void back()
{
displyvalue=true;
displyform=false;
}
}