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some queries in the program

 
Venkat Ramsimha
Ranch Hand
Posts: 127
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hi all,
consider the following program:
import java.util.*;
public class VecNum
{
public static void main(String argv[])
{
Vector v = new Vector();
v.add(new Integer(1));
v.add(new Integer(2));
for(int i=0; i < v.size();i ++)//line1
{
Integer iw =(Integer) v.get(i);//line2
System.out.println(iw.intValue());//line3
}

}

}

In the above program i have some queries:
1.why we need to use vector for wrapping all the integer values
2.what is the purpose of using line1,line2,line3
3.when i compile this program its generating errors

tx
carl..
tx
 
Rob Harris
Greenhorn
Posts: 10
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Carl,

1. You're not using a Vector to wrap your integer values, you're using the Integer Wrapper class. This turns your int primitives into Objects so they can be added to the collection.

2. Lines 1, 2 and 3 retrieve the Integer objects from the Vector. Vector.size() returns the number of components in the Vector and get() retrieves the objects using their index (just like an array).

3. The code compiles and runs fine for me.

Hope this helps!

Rob
SCJP 1.4
 
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