prowessapps.in Programs Using Class and Objects

 WAP to display "Hello World!" (enclosed in double quotes).

class Test {
 void display() {
  System.out.print("\"Hello World!\"");
 }
 public static void main(String[] a) 
 {
  Test t = new Test();
  t.display();
 }
}
OUTPUT :
"Hello World!"

 Define a class named Employee with the following fields: empID , empName , deptID , bloodGroup , salary.
Define following methods :
setEmployeeDetails( ), printEmployeeDetails( )
Prompt the user to enter values.

import java.util.Scanner;
class Employee {
 int empID,deptID,salary;
 String empName,bloodGroup;
 void setEmployeeDetail() {
  Scanner s=new Scanner(System.in);
  System.out.print("Enter empId: ");
  empID=Integer.parseInt(s.nextLine());
  System.out.print("Enter Name: ");
  empName = s.nextLine();
  System.out.print("Enter Dept. Id: ");
  deptID=Integer.parseInt(s.nextLine());
  System.out.print("Enter Blood Group: ");
  bloodGroup= s.nextLine();
  System.out.print("Enter Salary: ");
  salary=Integer.parseInt(s.nextLine());
 }
 void printEmployeeDetails() {
  System.out.println("EMP. ID - "+empID+
          "\nEMP NAME - "+empName+
           "\nDEPT ID - "+deptID+
          "\nBLOOD GROUP - "+bloodGroup+
          "\nSALARY - "+salary);
 }
 public static void main(String[] a)
 {
  Employee e = new Employee();
  e.setEmployeeDetail();
  e.printEmployeeDetails();
 }
}
OUTPUT :
Enter empId: 12
Enter Name: Alok
Enter Dept. Id: 5
Enter Blood Group: A
Enter Salary: 30000
EMP. ID - 12
EMP NAME - Alok
DEPT ID - 5
BLOOD GROUP - A
SALARY - 30000

 WAP to produce a table of Celsius and the equivalent Fahrenheit temperatures from 0 to 10.

class Temp {
 float convert(int c) {
  float f = (float)9.0/5*c;
  return f+32;
 }
 public static void main(String[] a)
 {
  Temp t = new Temp();
  System.out.println("Celc.\tFahren.");
  for(int i=1; i<=10; i++) {
   float x = t.convert(i);
   System.out.println(i+"\t"+x);
  }
 }
} 
OUTPUT :
Celc.   Fahren.
1       33.8
2       35.6
3       37.4
4       39.2
5       41.0
6       42.8
7       44.6
8       46.4
9       48.199997
10      50.0

 Write a program to calculate the area of circle and cylinder by creating methods named areaOfCircle and areaOfCylinder in a class named Area and using a constant variable PI=3.14.

import java.util.Scanner;
class Area {
 final double PI = 3.14;
 void areaOfCircle(int r) {
  double ar = PI*r*r;
  System.out.println("Circle Area= "+ar);
 }
 void areaOfCylinder(int r, int h) {
  double ar = 2*PI*r*h;
  System.out.print("Cylinder Area= "+ar);
 }
 public static void main(String[] a)
 {
  Area ar = new Area();
  Scanner s=new Scanner(System.in);
  System.out.print("Enter Circle Radius: ");
  int r = s.nextInt();
  System.out.print("Enter Cylinder Radius: ");
  int r2 = s.nextInt();
  System.out.print("Enter Cylinder Height: ");
  int h = s.nextInt();
  ar.areaOfCircle(r);
  ar.areaOfCylinder(r2,h);
 }
}  
OUTPUT :
Enter Circle Radius: 7
Enter Cylinder Radius: 7
Enter Cylinder Height: 10
Circle Area= 153.86
Cylinder Area= 439.6

 WAP to find the factorial of a number.

import java.util.Scanner;
class Test {
 public int factorial(int x) {
  int f = 1;
  for(int i = 1; i<=x; i++) {
   f = f*i;
  }
  return f;
 }
}
class Demo {
 public static void main(String[] a)
 {
  Test t = new Test();
  Scanner s=new Scanner(System.in);
  System.out.print("Enter a Num: ");
  int x = s.nextInt();
  int fact = t.factorial(x);
  System.out.print("Result = "+fact);
 }
}
OUTPUT :
Enter a Num: 6
Result = 720

 WAP to find out nCrusing static method.
Formula : nCr = n!/((n-r)!*r!)

import java.util.Scanner;
class Test {
 public static float fact(int x) {
  int f = 1;
  for(int i = 1; i<=x; i++) {
   f = f*i;
  }
  return f;
 }
 public static void main(String[] a)
 {
  Scanner s=new Scanner(System.in);
  System.out.print("Enter N: ");
  int n = s.nextInt();
  System.out.print("Enter R: ");
  int r = s.nextInt();
  float res=fact(n)/(fact(n-r)*fact(r));
  System.out.print("Result = "+res);
 }
}
OUTPUT :
Enter N: 5
Enter R: 3
Result = 10.0 


 WAP to demonstrate constructor Overloading.

class Rectangle { 
 int l, b;
 Rectangle() {
  l = 5;
  b = 3;
 }
 Rectangle(int l, int b) {
  
  this.l = l;
  this.b = b;
 }
 void area() {
  System.out.println("Area- "+(l*b));
 }
}
class Main {
 public static void main(String[] a)
 {
  Rectangle r =new Rectangle();
  r.area();
  Rectangle r2 = new Rectangle(20,10);
  r2.area();
 }
}
OUTPUT :
Area- 15
Area- 200

 Define a class named Test with an instance variable num.
Define a Constructor and a method named getReverse().
Create an object of the class pass an integer to the constructor to initialize num. Call getReverse() to get the reverse and print the reverse no.

import java.util.Scanner;
class Test {
 int x;
 Test(int num){
  x = num ;
 }
 int getReverse() {
  int temp, rev =0;
  while(x != 0) {
   temp = x%10;
   rev = rev *10+temp;
   x = x/10;
  }
  return rev;
 }
 public static void main(String[] a)
 {
  Scanner s=new Scanner(System.in);
  System.out.print("Enter Num: ");
  int x = s.nextInt();
  Test t = new Test(x);
  int res = t.getReverse();
  System.out.print("Reverse = "+res);
 }
}
OUTPUT :
Enter Num: 15465
Reverse = 56451

 WAP to demonstrate, passing an object as an argument.

class Demo {
 int a;
 Demo(int a) {
  this.a = a;
 }
}
class Test {
 int x = 20;
 void square(Demo d) {
 d.a = d.a*d.a;
 }
}
class Main{
 public static void main(String[] a)
 {
  Demo d = new Demo(10);
  Test t = new Test();
  System.out.println("Before Call- "+d.a);
  t.square(d);
  System.out.print("After Call- "+d.a);
 }
}
OUTPUT :
Before Call- 10
After Call- 100 

 Write a program to demonstrate the difference between static and non-static variables.

class Test {
 int a = 5;
 static int b = 5;
 void display() {
  a++;
  b++;
  System.out.println("A = "+a);
  System.out.println("B = "+b);
 }
 public static void main(String[] a)
 {
  Test t = new Test();
  t.display();
  Test t2 = new Test();
  t2.display();
  Test t3 = new Test();
  t3.display();
 }
}
OUTPUT :
A = 6
B = 6
A = 6
B = 7
A = 6
B = 8

 WAP to count , how many times a method is called using different object.

class Counter {
 static int count = 0;
 void counter(){
  count++;
 }
 void display() {
  System.out.println("Total time- "+count);
 }
 public static void main(String[] a)
 {
  Counter c = new Counter();
  c.counter();
  c.counter();
  Counter c2 = new Counter();
  c2.counter();
  c2.counter();
  c2.display();
 }
}
OUTPUT :
Total time-4




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