CODE: BINARY SEARCH SOUCE CODE

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package binarysearch;

/**
 *
 * @author samuel albert
 */
import java.util.Scanner;
public class BinarySearch {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
         int c, first, last, middle, n, search, array[];

    Scanner in = new Scanner(System.in);
    System.out.println("Enter number of elements");
    n = in.nextInt();
    array = new int[n];

    System.out.println("Enter " + n + " integers");
   
      for (c = 0; c < n; c++)
      array[c] = in.nextInt();

    System.out.println("Enter value to find");
    search = in.nextInt();

    first  = 0;
    last   = n - 1;
    middle = (first + last)/2;

    while( first <= last )
    {
      if ( array[middle] < search )
        first = middle + 1;   
      else if ( array[middle] == search )
      {
        System.out.println(search + " found at location " + (middle + 1) + ".");
        break;
      }
       else
         last = middle - 1;

      middle = (first + last)/2;
   }
   if ( first > last )
      System.out.println(search + " is not present in the list.\n");
        // TODO code application logic here
    }
   
}

CODE: DIVIDE AND CONQUER SOURCE CODE

package divide_and_conquer;

/**
 *
 * @author samuel albert
 */
import java.util.Scanner;
public class Divide_and_conquer {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Scanner s=new Scanner(System.in);
        System.out.println("YOU HAVE FOLLOWING CHOICES : ");
        System.out.println("1. ADDITION");
        System.out.println("2. SUBTRACTION ");
        System.out.println("3. MULTIPLICATION ");
        System.out.println("4. DIVISION");
        System.out.println("ENTER YOUR CHOICE : ");
        int i=s.nextInt();
          
        System.out.println("ENTER FIRST NUMBER ");
        int a=s.nextInt();
          
        System.out.println("ENTER SECOND NUMBER ");
        int b=s.nextInt();
       
        double result=0;//'result' will store the result of operation
          
        switch(i)
        {
            case 1:
                result=a+b;
                break;
            case 2:
                result=a-b;
                break;
            case 3:
                result=a*b;
                break;
            case 4:
                if(b==0)//when denominator becomes zero
                {
                    System.out.println("DIVISION NOT POSSIBLE");
                    break;
                }
                else
                    result=a/b;
               
                default:
                System.out.println("YOU HAVE ENTERED A WRONG CHOICE");
           
        }
          
        System.out.println("RESULT = "+result);
        // TODO code application logic here
    }
   
}