Searching for an Element

Linear search is starting at the first element and examining them one by one until the target element is found. You could write linear search for a Vector (and it would be a good exercise to do so); but there is a method that does this for you:

int indexOf(Object elem)    //  Search for the first occurrence of 
                            //  elem, testing for equality 
                            //  using the equals method of elem. 

The method returns the index of the first occurrence of elem or -1 if elem is not found.

import java.util.* ;
class VectorEg
{
  public static void main ( String[] args)
  {
    Vector names = new Vector( 10 );

    names.addElement( "Amy" );    names.addElement( "Bob" );
    names.addElement( "Chris" );  names.addElement( "Deb" );
    names.addElement( "Chris" );  names.addElement( "Joe" );

     System.out.println( names.indexOf( "Bob" ) ); 
     System.out.println( names.indexOf( "Elaine" ) ); 
  }
}