public class College
{
 // college name.
 Public Static final String CollegeName ='Tirumala Engg College';
 // college address.
 public Static final String  CollegeAdress='kesaraGutta,Bogaram,Hyderabad.';
 //college Year of Establishment.
 public Static final Integer DOE=1990;
 // creating Student class
 public class StudentClass
  {
  // creating properties for the required Student feilds(student number,student name,student address etc).
   public Integer sNo{get;set;}
   public String sName{get;set;}
   public String sAddress{get;set;}
   public Integer doj{get;set;}
   public String course{get;set;}
  }
  public class InstructorClass
  {
  // creating properties for Instructor feilds.
   public Integer iNo{get;set;}
   public String iName{get;set;}
   public String iQualification{get;set;}
   public Integer iDeptno{get;set;}
   }
   public class DeptClass
  {
  //creating properties for Department feilds.
   public Integer deptNo{get;set;}
   public String deptName{get;set;}
   public String deptLoc{get;set;}
   }
   //creating a list of students
   public List<StudentClass> students =new List<StudentClass>();
   ////creating a list of Instructors
   public List<InstructorClass> instructors =new List<InstructorClass>();
   //creating a list of Departments
   public List<DeptClass> departments =new List<DeptClass>();
   
  /* public String College()
   {
    return 'Welcome to '+ College.CollegeName;
    }*/
    
    public static StudentClass searchStudent(Integer stNo,List<StudentClass> Stds)
    {
       for(College.StudentClass student:stds)
         {
          if(Stds.sNo==stNo)
           {
           return student;
           }
           }
           }
    }
    
    hi can tell what's the error , am unable to understand error. any suggestion