Code by Ved

 interface ICalculator{ // public and abstract void add(int a, int b); void sub(int a, int b); void mul(int a, int b); void div(int a, int b); } class Cal implements ICalculator{   public void add(int a , int b){       System.out.println("the sum is="+(a+b));   }   public void sub(int a , int b){       System.out.println("the subtraction is="+(a-b));   }   public void mul(int a , int b){       System.out.println("the multiplication is="+(a*b));   }   public void div(int a , int b){       System.out.println("the division is="+(a/b));   } } public class Main { public static void main(String[] args) { ICalculator c = new Cal(); c.add(10,20); c.sub(4,2); c.mul(2,8);     c.div(9,3); } } ------------------------------------------------------------------------------------------------------------------ interface ICalculator1{ // public and abstract void add(int a,...

Inheritance--- --------------------------- class person{     public int age;     public String name;     public String address; } class Student extends person{     public int marks;     public String grade;     Student(int age , String name , String address , int marks , String grade){         this.age=age;         this.name=name;         this.address=address;         this.marks=marks;         this.grade=grade;     }     public void disp(){         System.out.println("age is ="+age);         System.out.println("name is ="+name);         System.out.println("address is ="+address);         System.out.println("marks is ="+marks);         System.out.println("grade is ="+grade);     } } public class Main { ...

 public class Main { public static void main(String[] args) { String[] arr={"67983547","0078","78","564","3424"}; String mx=arr[0]; for(int i=1; i<arr.length; i++){     mx=maxstr(mx,arr[i]); } System.out.println(mx); } public static String maxstr(String a , String b){     String s=purify(a); String t=purify(b);     if(s.length()>t.length()) return a;     if(t.length()>s.length()) return b;     for(int i=0; i<s.length(); i++){         if(s.charAt(i)!=t.charAt(i)){             if(s.charAt(i)>t.charAt(i))             return a;             else             return b;         }     }     if(a.length()>=b.length()) return a;     else return b; } public static String purify(String a)...

  package program ; import java . util . Scanner ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter string in lower case :" );     String s = sc . next ();     int [] frqArr = new int [ 26 ];     for ( int i = 0 ; i < s . length (); i ++ ){         int as = s . charAt ( i );         frqArr [ as - 97 ] ++ ;     }     int mx =- 1 ;     for ( int i = 0 ; i < frqArr . length ; i ++ ){         if ( frqArr [ i ] > mx ){             mx = frqArr [ i ];         }       }     System . out . println ( "character with max occurrence :" );     for ( int i = 0 ; i < frqArr . length ; i ++ ){         if ( frqArr [ ...

import java.util.Scanner; public class Main { public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("enter string=");       String s = sc.nextLine();       System.out.println("enter character=");       char ch = sc.next().charAt(0);       int ix=-1;       for(int i=s.length()-1; i>=0; i--){             if(ch==s.charAt(i)){                   ix=i;                   break;             }       }       System.out.println(ix);       } }

  package program ; import java . util . Scanner ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter string=" );     String s = sc . nextLine ();     System . out . println ( "enter a character=" );     char ch = sc . next (). charAt ( 0 );     int ix =- 1 ;     for ( int i = 0 ; i < s . length (); i ++ ){         if ( ch == s . charAt ( i )){         ix = i ;         break ;         }     }         System . out . println ( ix );     } }

package program ; import java . util . Scanner ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter string=" );     String s = sc . nextLine ();     System . out . println ( s );     } } String Methods -> charAt()- package program ; import java . util . Scanner ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     String s = "ved varshney" ;     System . out . println ( s . charAt ( 2 ));     } } length()- package program ; import java . util . Scanner ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     String s = "ved varshney" ;     System . out . println ( s . leng...

  package L inked L ist ; class Sll {     Node head ;     Node tail ;     int size ;     void length (){         System . out . println ( "length is = " + size );     }     void insertAtStart ( int val ){     Node temp = new Node ( val );     if ( head == null ){         head = tail = temp ;         size ++ ;         return ;     }     temp . next = head ;     head = temp ;     size ++ ;     }     void insertAtEnd ( int val ){     Node temp = new Node ( val );     if ( tail == null ){         head = tail = temp ;         size ++ ;         return ;     }     tail . next = temp ;     tail = temp ;     size ++ ;     } ...