JAVA
Interfaces
and Packages & java.util Package
Fill
in the blanks
1.Write a
keyword for interface implements
2.Write a
keyword for class to class extends
3.Write a
keyword for class to interface implements
4.Collection
of class and object is called package
5.We can use
one file to another program by using
import .[T/F] True.
6.Vector implements
a dynamic array.
7.One of the
ways to store information for fast lookup is a hase table.
8.To make use
of classes within different packages , the import statement is used.
9.Obtained
the element at a specific location elementAt() method is used.
10.To remove
an element removeElement() method is used.
Answer
the Following Questions
(4
marks)
1.Write a
program to calculate area of rectangle & area of circle using Interface
File name: Area.java
interface Area
{
final
static double pi=3.14;
double
compute(double x,double y);
}
File name: Rect1.java
class Rect1 implements Area
{
public
double compute(double x, double y)
{
return(x*y);
}
}
File name: Circle.java
class Circle implements Area
{
public
double compute(double x, double y)
{
return(pi*x*x);
}
}
File name: InterfaceTest.java
class InterfaceTest
{
public
static void main(String args[])
{
Rect1
r=new Rect1();
Circle
c=new Circle();
Area
area;
area=r;
System.out.println("Area
of the Rectangle = "+area.compute(10,20));
area=c;
System.out.println("Area
of the Rectangle = "+area.compute(10,0));
}
}
2.Write a program
for Vector
File name: VectorDemo.java
import java.util.*;
public class VectorDemo {
public static
void main(String []args) {
Vector<String>
vectStr = new Vector<String>(); //Declaring a Vector in Java
vectStr.add("apple");
vectStr.add("orange");
vectStr.add("graphs");
//Displaying
vector elements
System.out.println("The
Vector elements are:");
System.out.println("");
for
(int i=0;i<vectStr.size();i++){
System.out.println(vectStr.get(i));
}
}
}
Answer
the Following Questions
(10
marks)
1.Write a program a package using Math function
File Name : MathFun.java
package Math;
public class MathFun
{
public int fact(int num)
{
if(num==1)
return
1;
else
return(num*fact(--num));
}
public int square(int num)
{
return(num*num);
}
public int cube(int num)
{
return(num*num*num);
}
public int sum(int a,int b)
{
return(a+b);
}
public float sum(float a, float b)
{
return(a+b);
}
public float multiply(float a, float b)
{
return(a*b);
}
}
//File Name: PackTest.java
import Math.MathFun;
class PackTest
{
public static void
main(String args[])
{
MathFun mf=new MathFun();
System.out.println("Factorial:"+mf.fact(5));
System.out.println("Square:"+mf.square(5));
System.out.println("Cube:"+mf.cube(5));
System.out.println("Sum of Two
Interger:"+mf.sum(5,5));
System.out.println("Sum of Two
float Number:"+mf.sum(5.5f,5.3f));
}
}
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