28_Exception handling

package com.company;


public class try_catch {
    public static void main(String[] args) {
        int a = 3000;
        int b = 0;
        try{
            int c = a/b;
            System.out.println("The result is:" +c);
        }
        catch (Exception e){
            System.out.println("We failed to divide. Reason: ");
            System.out.println(e);
            System.out.println("End of the program");
        }
    }
}

// Specific exceptions

package com.company;

import java.util.Scanner;

public class Specific_exceptions {
    public static void main(String[] args) {
        int[] marks = new int[3];
        marks[0]=30;
        marks[1]=38;
        marks[2]=49;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the array index: ");
        int ind = sc.nextInt();

        System.out.println("Enter the number you want to dic=vide with: ");
        int number = sc.nextInt();
        try{
            System.out.println("The value at array index entered is: " +marks[ind]);
            System.out.println("The value of array-value/number is: "+marks[ind]/number);
        }
        catch (ArithmeticException e){
            System.out.println("Some exception occured!");
            System.out.println(e);
        }
        catch (ArrayIndexOutOfBoundsException e){
            System.out.println("Some exception occured!");
            System.out.println(e);
        }
        catch (Exception e){
            System.out.println("Some other exception occured!");
            System.out.println(e);
        }
    }
}


//Nested try-catch

package com.company;

import java.util.Scanner;

public class Nested_try_catch {
    public static void main(String[] args) {
        int[] marks = new int[3];
        marks[0]=30;
        marks[1]=38;
        marks[2]=49;
        Scanner sc = new Scanner(System.in);
        boolean flag = true;
        while (flag) {

            System.out.println("Enter the array index: ");
            int ind = sc.nextInt();
            try {
                System.out.println("Welcome to this world");
                try {
                    System.out.println(marks[ind]);
                    flag = false;
                } catch (ArrayIndexOutOfBoundsException e) {
                    System.out.println("Sorry this index does not exist!");
                    System.out.println("Exception in level 2");
//                    flag = false;
                }
            } catch (Exception e) {
                System.out.println("Exception in level 1");
            }
        }
    }
}


//Exception class

package com.company;

import java.util.Scanner;

class MyException extends Exception{
    @Override
    public String toString(){
        return super.toString();
        }

    @Override
    public String getMessage() {
        return super.getMessage();
    }
}
public class Exception_class {
    public static void main(String[] args) {
        int a;
        Scanner sc = new Scanner(System.in);
        a=sc.nextInt();
        if (a<9){
            try {
                throw new  MyException();
            }
            catch(Exception e){
                System.out.println(e.getMessage());
                System.out.println(e.toString());
                e.printStackTrace();
            }
        }
    }
}


//throw-throws kwywords

package com.company;

class NegativeRadiusException extends Exception{
    @Override
    public String toString() {
        return "Radius cannot be negative";
    }

    @Override
    public String getMessage() {
        return "Radius cannot be negative";
    }
}
public class Throw_throws {
    public static double area(int r) throws NegativeRadiusException{
        if (r<0){
            throw new NegativeRadiusException();
        }
        double result = Math.PI*r*r;
        return result;
    }
    public static int divide(int a, int b) throws ArithmeticException{
        int result = a/b;
        return result;
    }
    public static void main(String[] args) {
        try {
//            int c = divide(3,3);
//            System.out.println(c);
            double ar = area(0);
            System.out.println(ar);
        }
        catch (Exception e){
            System.out.println("Exception");
        }
//        double ar = area(5);
    }
}


// finally keyword

package com.company;

public class Finally {
    public static int greet() {
        try {
            int a = 60;
            int b = 4;
            int c = a / b;
            return c;
        } catch (Exception e) {
            System.out.println(e);
        } finally {
            System.out.println("This is the end of this function");
        }
        return 0;
    }
    public static void main(String[] args) {
//        try {
//            int a = 5;
//            int b = 0;
//            int c = a/b;
//        }
//        catch (Exception e){
//            System.out.println(e);
//        }
//        finally {
//            System.out.println("This is the end of this program");
            int k = greet();
        System.out.println(k);
        }
    }