Searching and Sorting - A Concise and Practical Introduction to Programming Algorithms in Java - page 130

class Person{
String firstname, lastname; // key for searching
String phone; // additional fields go here

// Constructor
Person(String l, String f, String p)
{this.firstname=f; this.lastname=l; this.phone=p;}
};

Let us consider the keys of objects as the lastname and firstname attributes,
and report the phone number record of the object in case the object is found
in the array. The sequential search algorithm is implemented by the following
LinearSearch function:

Program 6.2 Linear search on objects
static Person [] array= new Person[5];

static String LinearSearch(String lastname , String firstname)
for ( int i=0;i < array . length ; i++)
{ if (( lastname . equals ( array [ i ] . lastname) &&
(firstname . equals(array [ i ]. firstname))))
{ return array [ i ] . phone ; }
return "Not found in my dictionary" ;

}

Observe that the predicate for checking whether the keys of the current object
with the given query is not a single == comparison test but rather uses the
String method equals to check that the string contents are identical. The
program below demonstrates the sequential search on an array of Person
initialized. Observe that the array is defined as a static array so that its
data are attached to the program class and can therefore be accessed from the
various static functions of the class.

Program 6.3 A demonstration program using the Person object array
class LinearSearchProgram {
static Person [] array= new Person[5];

static String LinearSearch(String lastname , String
firstname)
{ ... }

public static void main ( String [ ] args )
{ array [0]= new Person( "Nielsen" , "Frank" , "0169364089" );
array [1]= new Person( "Nelson" , "Franck" , "04227745221" );
array [2]= new Person( "Durand" , "Paul" , "0381846245" );
array [3]= new Person( "Dupond" , "Jean" , "0256234512" );