CODEWITHSUNDEEP
javaandroidarrays
royi h
royi h

Reputation: 39

Accessing Objects of a 2 Diminsional Array

Which is more efficient, faster and why? Accessing the objects in the array directly or creating a temp object?

For android system i was told that direct access is better, faster and less garbage collection

   public static Foo [10][10];

   public class Foo{
   int score;
   int age;
   int type;
   }

Option One:

for(int col = 0; col < 10; col++)
    for(int row = 0; row < 10; row++){
    int temp = Foo[col][row].score;
    int temp_two = Foo[col][row].age;
    int temp_three = Foo[col][row].type;

    }

Option Two:

 for(int col = 0; col < 10; col++)
    for(int row = 0; row < 10; row++){
        Foo tempFoo = Foo[col][row];

        int temp = tempFoo.score;
        int temp_two = tempFoo.age;
        int temp_three = tempFoo.type;

    }

Thank you

Upvotes: 1

Views: 43

Answers (2)

Rakesh KR
Rakesh KR

Reputation: 6527

The best method is 2nd one and you can made a modification as follows,

public class Foo{
   private int score;
   private int age;
   private int type;

   // getters and setters for the variables
}

And do as,

for(int col = 0; col < 10; col++){
    for(int row = 0; row < 10; row++){
        Foo tempFoo    = Foo[col][row];
        int temp       = tempFoo.getScore();
        int temp_two   = tempFoo.getAge();
        int temp_three = tempFoo.getType();
    }
}

Upvotes: 1

Chriss
Chriss

Reputation: 5639

Option 2 will be faster cause the VM needs only one array lookup for your Foo Object, that means the array bounds have only be to checked once not 3 times.

Anyway, you can also use a foreach-loop, which is faster to read by others maybe by the VM too:

for(Foo[] row: rows)
    for(Foo foo: row){
        int temp = foo.score;
        int temp_two = foo.age;
        int temp_three = foo.type;
    }

Upvotes: 1

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