DrivingTest Project

public class Demo {

public static void main(String[] args) {

Car myCar = new Car();
myCar.fuelCapacity = 20;
myCar.amountOfFuel = 10 ;
myCar.addGas(5);
System.out.println(myCar.amountOfFuel);

myCar.mileage = 15;
myCar.drive(100);
}
}


class Car{
// first think of properties which is nown and then actions which is verb

double mileage;
double amountOfFuel;
double fuelCapacity;

public void drive(double distance){
double fuelNeeded = distance/mileage;
if (amountOfFuel >= fuelNeeded) {
amountOfFuel = amountOfFuel - fuelNeeded;
System.out.println("You travelled "+ distance+" KM");
} else {
System.out.println("You dont have sufficient amount of fuel for the trip");
}
}

public void addGas(double amt){
double emptySpace = fuelCapacity - amountOfFuel;
if (amt < emptySpace) {
amountOfFuel = amountOfFuel + amt;
System.out.println(amt + " liters is added successfully");
} else {
amountOfFuel = fuelCapacity;
System.out.println("Tank is full");
}


}

public double getFuelLevel(){
System.out.println(amountOfFuel);
return amountOfFuel;
}
}

Class

DEMO1:

// CLASS: Class Defines the blueprint for set of object of the same type
// OBJECT: Each object is unique real and has properties and action

public class ClassDemo1 {

public static void main(String[] args) {

Circle obj = new Circle();
obj.radius = 2.22;
obj.area = 3.14 * obj.radius * obj.radius ;
System.out.println("Obj1 area is: "+obj.area);

Circle obj2 = new Circle();
obj2.radius = 5.55;
obj2.area = 3.14 *obj2.radius*obj2.radius;
System.out.println("Obj2 area is: "+obj2.area);
}
}


class Circle{

double radius ;
double area ;

}

DEMO2:


public class ClassDemo2 {

public static void main(String[] args) {

CircleClass obj1 = new CircleClass();
obj1.findArea(2.22);

CircleClass obj2 = new CircleClass();
obj2.findArea(5.55);
}
}


class CircleClass{

double radius;
double area;

public void findArea(double radius) {

this.radius = radius;
area = 3.14 * this.radius * this.radius ;
System.out.println("The area is: "+area);
}

}

Object

Properties and Action:

Object:

// Object is the combination of properties and actions
// Properties is noun and Actions are Verb

// CLASS: Class Defines the blueprint for set of object of the same type
// OBJECT: Each object is unique real and has properties and action

// obj1 and obj2 which is the object reference hold different space in the memory.
// object is made by calling the constructor

public class ObjectDemo {

public static void main(String[] args) {

CircleClass obj1 = new CircleClass();
obj1.findArea(2.22);

CircleClass obj2 = new CircleClass();
obj2.findArea(5.55);
}
}


class CircleClass{

double radius;
double area;

public void findArea(double radius) {

this.radius = radius;
area = 3.14 * this.radius * this.radius ;
System.out.println("The area is: "+area);
}

}

Method Overloading

// Methods within the same class that have the same name but slightly different characteristics
// like different number of parameters , different type of parameters that performed the related
// operations are called overloaded methods

// Overloaded method causes ambiquous invocation lead to compile error


public class MethodOverloadingDemo {

public static void main(String[] args) {

Maths math = new Maths();
double res = math.max(2.0, 4.0);
System.out.println(res);

int resu = math.max(2, 4);
System.out.println(resu);

double resul = math.max(2, 4.0);
System.out.println(resul);
}
}


class Maths{

public int max(int x , int y) {
int maximum;
if ( x > y) {
maximum = x;
}else{
maximum = y;
}
System.out.println("\n integer version is called");
return maximum;
}

public double max(double x , double y) {
double maximum;
if ( x > y) {
maximum = x;
}else{
maximum = y;
}
System.out.println("\n double version is called");
return maximum;
}
}

Method CallStack

------------------------------------------------------------------------------------------------------------------------

package packageName;

public class MethodCallStackDemo {

public static void main(String[] args) {

int maximum = max(5, 10);
System.out.println("Maximum between two no is: "+maximum);

int minimum = min(5, 10);
System.out.println("Minimum between two no is: "+minimum);

}


public static int max(int x , int y) {

int maximum;
if (x > y) {
maximum = x ;
} else {
maximum = y;
}
return maximum;
}


public static int min(int x, int y) {

int minimum;
if (x < y) {
minimum = x;
}else{
minimum = y;
}
return minimum;
}
}

Methods

// When to make the methods?
// Is that the single operation you want to do
// Does it needs several steps to do that exact operations

public class MethodDemo1 {

public static void main(String[] args) {

add();
add(20, 30);

int res = add(30, 40, 50);
System.out.println("SmartMethod: "+res);

}

// DUMB METHOD: When calling this method it always add 10 and 20 and
// print the result in console and do not return anything

public static  void add() {
int a=10,b=20;
int result = a + b;
System.out.println("DumMethod: "+result);
}

// CLEVER METHOD: When calling this method it ask user to what numbers
// are to add and print the  result in console and do not return anything

public static void add(int a, int b){
int result = a + b;
System.out.println("CleverMethod: "+result);
}

// SMART METHOD: When calling this method it ask user to what numbers are
// to add and  it return the int value which is first not shown in the console and
// it can later on put in certain int variable and display as an output using syso

public static int add(int a , int b , int c){
int result = a + b+ c;
return result;
}
}

Naming Convention