This section contains problems along with their answers .


Q) Write a program to convert number into word.
Example :
Input -234	
Output-Two Thee Four

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import java.util.*;  //importing package
class Convert //class name
{  //opening class 

    Scanner ob = new Scanner(System.in); //creating object of scanner class
    int n;    //initializing n

    Convert() //  non parameterize constructor
    {          //opening constructor
        n = 0;  //initializing n with 0
    }          //closing constructor

    void input() throws Exception //method to input value
    {
        System.out.print("Enter the Number:");
        n = ob.nextInt();
    }

    void extdigit(int a) //method to covert number to word by extracting each digit 
    {
        int dig = 0;   //extra variable
        if (a == 0) //condition
        {
            return;
        } else {
            dig = a % 10;
            extdigit(a / 10);  //recalling method 
            num_to_word(dig); //calling method which convert no. to word
        }
    }

    void num_to_word(int b) //fuction to covert number to word
    {
        switch (b) {

            case 0:
                System.out.print("Zero ");   //if digit is 0 then print zero
                break;//break 

            case 1:
                System.out.print("One ");    //if digit is 1 then print one
                break;

            case 2:
                System.out.print("Two ");   //if digit if 2 then print two
                break;
            case 3:
                System.out.print("Three ");   //if digit if 3 then print three
                break;
            case 4:
                System.out.print("Four ");   //if digit if 4 then print four
                break;
            case 5:
                System.out.print("Five ");   //if digit if 5 then print five
                break;
            case 6:
                System.out.print("Six ");    //if digit if 6 then print six
                break;
            case 7:
                System.out.print("Seven ");   //if digit if 7 then print seven
                break;
            case 8:
                System.out.print("Eight ");   //if digit if 8 then print eigth
                break;
            case 9:
                System.out.print("Nine ");   //if digit if 9 then print nine
                break;
        }
    }

    public static void main(String ar[]) //main method    
    {
        System.out.print("Enter Number :");    //input a number 

        Convert ob1 = new Convert();
        int c = ob1.ob.nextInt();//creating object of convert class
        ob1.extdigit(c);   //method calling
    }   //closing main
}   //closing class

Output:

Enter Number :2335
Two Three Three Five


Q) Write a Program for checking whether a string is palindrome or not using Recursion.
E.g.  NITIN is a  palindrome String because 
 if reverse String  we get same as primary String
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import java.util.*;   //importing package
class pallindrome //class name
{//opening class  

    Scanner ob = new Scanner(System.in);   //creating object of scanner class
    String str;//intializing 
    String Revst; // string to store reverse of original string

    pallindrome() //non parameterize constructor
    {
        str = null;   //initializing str with null
        Revst = " "; //initializing with empty
    } //closing constructor

    void input() throws Exception //method to input value
    {
        System.out.print("Enter the sentence:");
        str = ob.nextLine();
        Revst = " ";
        recReverse(str.length() - 1);
    }

    void recReverse(int a) {
        if (a < 0) {
            return;
        } else {
            Revst = Revst + str.charAt(a);
            recReverse(a - 1);
        }
    }

    void check() //mehtod to check pallindrome string
    {
        Revst = Revst.trim();// to remove space from beginning
        System.out.println("Entered String :" + str);
        System.out.println("Reverse String :" + Revst);

        if (str.equals(Revst)) //if revst is excactly equal to str
        {
            System.out.print("it is pallindrome string");   //then it is pallindrome string
        } else//else
        {
            System.out.print("it is not pallindrome string");  //it is not a pallindrome string
        }
    }   //cloasing function

   public static void main(String arr[]) throws Exception //main method
    {//opening main
        pallindrome ob1 = new pallindrome();    //creating object of pallindrome class
        ob1.input();   //calling method to input
        ob1.check();  //calling method to check
    }  //closing main
}  //closing class

Output:

Enter the sentence:NITIN
Entered String :NITIN
Reverse String :NITIN
it is pallindrome string


Q) Write a program accept a sentence from user and print the initial of word in sentence except last word of a sentence and print in following format
Input-  sachin ramesh tendulkar
Output - TENDULKAR   S.   R.
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import java.util.*;  // importing util package
class initials  //class name
{
public static void main (String arg[])throws Exception 
{
Scanner ob=new Scanner (System.in);  //creating object of scanner class
System.out.print("Enter the Sentence");  //inputting value from user
String s=ob.nextLine();
s=s.toUpperCase();    //converting into upper case
int l=s.lastIndexOf(' ');   //initialing l with last index of space
String s1=s.substring(l);
s=" "+s;//adding space in at index -1
System.out.print(s1+" ");  //printing modified string

for(int i=0;i<=l;i++)   //loop till last index of space 
{
char ch=s.charAt(i);  //extracting each character
if(ch==' ')
{
char chh=s.charAt(i+1);
if(Character.isLowerCase(chh))
{
  System.out.print((char)(chh-32)+"."+" ");
}
else
  System.out.print((chh)+"."+" "); //printing string
}
}
}  // closing main
} //closing class

Output:

Enter the Sentence 
Sachin Ramesh Tendulkar
 TENDULKAR S. R.


Q)Write a Program to print a circular Matrix.
E.g. if a   number is 3
Then output is-
1	2	3	
8	9	4	
7	6	5	


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import java.util.*;   //importing util pckage

class circularMatrix //name of class
{  //opening class
    public static void main(String[] args) //main function
    {   //openiing main
        Scanner ob = new Scanner(System.in);   //creating object of scanner class
        System.out.print("Enter the number ");// input from a user
        int n = ob.nextInt();
        int t = n;   //coppying value of n to t
        int[][] s = new int[n][n];  //declearing matrix n*n
        int r = (n % 2 == 0) ? (n / 2) : ((n + 1) / 2);
        int c = 1; //extra variable to perform specific operation
        int x = 0;  //temporary variable initializing with 0
        int y = 0;  //temporary variable initializing with 0
        for (int i = 1; i <= r; i++) //loop
        {
            for (int j = 1; j <= (4 * n - 4) || (j == 1); j++) //loop for rotation 
            {
                s[x][y] = c;//
                c++;
                if (j < n || j == (4 * n - 4)) {
                    y++;//increasing y
                } else if (j < (2 * n - 1)) {
                    x++;//increasing x
                } else if (j < (3 * n - 2)) {
                    y--;//decreasing y
                } else if (j < (4 * n - 4)) {
                    x--;//decreasing x
                }
            }
            n = n - 2;
        }

        for (int i = 0; i < t; i++)//loop to print 
        {
            for (int j = 0; j < t; j++) {
                System.out.print(s[i][j] + "\t");//printing whole matrix
            }
            System.out.println();
        }
    }//closing main
}//closing class

Output:

Enter the number 4
1	2	3	4	
12	13	14	5	
11	16	15	6	
10	9	8	7	


Q) Write a Program to print a spiral matrix.
E.g. 
 if the number is  3
Then output is-
9	8	7	
2	1	6	
3	4	5
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import java.util.*; //importing a util package

class spiralMatrix //name of the class
{//opening class

    public static void main(String[] args) { //opening main
        Scanner ob = new Scanner(System.in);//creating object of scanner class
        System.out.print("Enter the number "); //input a number from user
        int n = ob.nextInt();			//accepting size of array
        int t = n;
        int[][] s = new int[n][n];		//declaring array
        int r = (n % 2 == 0) ? (n / 2) : ((n + 1) / 2);	//calculating rotations
        int c = n * n;					//initializing first value
        int x = 0;
        int y = 0;
        for (int i = 1; i <= r; i++) //loop		
        {
            for (int j = 1; j <= (4 * n - 4) || (j == 1); j++)//loop for rotation
            {
                s[x][y] = c;//transfersing values to matrix
                c--;
                if (j < n || j == (4 * n - 4)) {
                    y++;
                } else if (j < (2 * n - 1)) {
                    x++;
                } else if (j < (3 * n - 2)) {
                    y--;
                } else if (j < (4 * n - 4)) {
                    x--;
                }
            }
            n = n - 2;
        }
        for (int i = 0; i < t; i++)//loop for printing 
        {
            for (int j = 0; j < t; j++) {
                System.out.print(s[i][j] + "\t");// massage displayed
            }
            System.out.println();//changing line
        }
    }//end main
}//end class

Output:

Enter the number 4
16	15	14	13	
5	4	3	12	
6	1	2	11	
7	8	9	10	


Q) Write a program to print a febnoci series .
Febnoci series - 0 1 1 2 3 5 8 13?.
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import java.util.*; //importing package

class febnoci //class name 
{//opening class

    int print(int step) //function to print the steps of series 
    {
        if (step <= 1) //step is <0
        {
            return step;
        } else {
            return (print(step - 1) + print(step - 2));  //recalling the function using recursion
        }
    }

    public static void main(String arg[]) //main function
    {  //opening main
        Scanner o = new Scanner(System.in);
        febnoci ob = new febnoci();  //creating a object of class created erlier
        System.out.print("Enter the Number:");
        int n = o.nextInt();
        for (int i = 0; i <= n; i++)//loop to print
        {  //opening loop
            System.out.print("\t" + ob.print(i));  //printing values of series
        }//closing loop
    }//closing main
}//closing class

Output:

Enter the Number:5
	0	1	1	2	3	5


Q) Write a program to print a pattern.
Input :
computer

Output-
computer
omputer
mputer
puter
uter
ter
er
r
r
re
ret
retu
retup
retupm
retupmo
retupmoc
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import java.util.* ;  //importing util package
   class Pattr //class name
   {//opening class
   public static void main(String args[])throws Exception
   {//opening main
   Scanner ob=new Scanner(System.in);  //creating object of scanner class
   System.out.println("Enter sentence");  //input string
   String s=ob.nextLine();
   int l=s.length(); //length of string in int a
   for(int i=0;i=0;i--) //2nd loop 
   {
   for(int j=l-1;j>=i;j--) //nested loop
   {
   System.out.print(s.charAt(j)); //printing 
   }
   System.out.println(); //going to next line
   }}}//closing loop/closing mai//closing class
               

Output:

Enter sentence
Computer

Computer
omputer
mputer
puter
uter
ter
er
r
r
re
ret
retu
retup
retupm
retupmo
retupmoC

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