Code by Ved

  import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter a string Builder=" );       StringBuilder sb = new StringBuilder ( sc . nextLine ());       int n = sb . length ();       for ( int i = 0 ; i < n / 2 ; i ++ ){         char temp = sb . charAt ( i );         sb . setCharAt ( i , sb . charAt ( n - 1 - i ));         sb . setCharAt ( n - 1 - i , temp );       }       System . out . println ( "reverse string Builder is=" );       System . out . println ( sb );       } } output-> enter a string Builder= ved reverse string Builder is= dev

 import java.util.*; public class Main { public static void main(String[] args) { Scanner sc=new Scanner(System.in); System.out.println("enter a string=");       StringBuilder sb=new StringBuilder(sc.nextLine());       int n=sb.length();       for(int i=0; i<n; i++){          int as=(int)(sb.charAt(i));          if(as>=97 && as<=122){             as=as-32;             sb.setCharAt(i,(char)as);          }else if(as>=65 && as<=90){             as=as+32;             sb.setCharAt(i,(char)as);          }       }       System.out.println("toggle string is=");       System.out.println(sb);       } } output-> enter a string= VedVAR...

 import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("enter string="); String str=sc.nextLine();       int count=0;       for(char c:str.toCharArray()){             count++;       }       System.out.println("length is="+count); } } output-> enter string= ved varshney length is=12

  import java . util .* ; public class code {     public static void main ( String [] args ) {     Scanner sc = new Scanner ( System . in );     System . out . println ( "enter string=" );     String str = sc . nextLine ();     int c = 0 ;     for ( int i = 0 ; i < str . length (); i ++ ){         char ch = str . charAt ( i );         if ( isvowel ( ch ) == true )         c ++ ;     }     System . out . println ( "total vowel are=" + c );     }     public static boolean isvowel ( char ch ){         if ( ch == 'a' || ch == 'A' ) return true ;         if ( ch == 'e' || ch == 'E' ) return true ;         if ( ch == 'i' || ch == 'I' ) return true ;         if ( ch == 'o' || ch == 'O' ) return true ;       ...

 import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("enter string="); String s=sc.nextLine(); String ans=""; for(int i=0; i<s.length(); i++){    if(i%2==0)    ans+="a";    else    ans+=s.charAt(i); } System.out.println("new string is="); System.out.println(ans); } } output-> enter string= ved varshney new string is= aea aaasanay

 import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("enter string="); String s=sc.next(); int n=s.length(); for(int i=0; i<n; i++){       for(int j=i+1; j<=n; j++){             System.out.print(s.substring(i,j)+" ");       }       System.out.println(); } } } output-> enter string= rohan r ro roh roha rohan  o oh oha ohan  h ha han  a an  n 

 import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("enter string="); String str=sc.nextLine(); System.out.println("enter character="); char ch=sc.next().charAt(0); int n=str.length(); int index=-1; for(int i=n-1; i>=0; i--){       if(ch==str.charAt(i))       {        index=i;        break;       } }     System.out.print("index is="+index); } } output-> enter string= ved varshney enter character= e index is=10

import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("enter string="); String str=sc.nextLine(); System.out.println("enter character="); char ch=sc.next().charAt(0); int n=str.length(); int index=-1; for(int i=0; i<n; i++){       if(ch==str.charAt(i))       {        index=i;        break;       } }     System.out.print("index is="+index); } } output-> enter string= java language enter character= v index is=2

 import java.util.*; public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("enter string="); String str=sc.nextLine(); int n=str.length(); int count=0; for(int i=0; i<n; i++){       char ch=str.charAt(i);       if(isvowel(ch)==true)       count++; } System.out.println("total vowels are="+count); } public static boolean isvowel(char ch){       if(ch=='a' || ch=='A') return true;       if(ch=='e' || ch=='E') return true;       if(ch=='i' || ch=='I') return true;       if(ch=='o' || ch=='O') return true;       if(ch=='u' || ch=='U') return true;       return false; } } output-> enter string= hey i am ved varshney total vowels are=6

 import java.util.Scanner; public class Main { public static void main(String[] args) {       Scanner sc = new Scanner(System.in);       System.out.println("enter row and column size=");       int m=sc.nextInt();       int n=sc.nextInt();       int[][] arr=new int[m][n];       System.out.println("enter elements=");       for(int i=0; i<m; i++){             for(int j=0; j<n; j++){                   arr[i][j]=sc.nextInt();             }       }       // logic       for(int i=0; i<m; i++){              if(i%2==0){                     for(int j=0; j<n; j++){                     System.out....