1. Java Program to find weather a given number is prime or not
Code:
import java.util.Scanner;
public class prime {
 public static void main(String args[])
 {
  int i,count=0;
  @SuppressWarnings("resource")
  Scanner sc = new Scanner(System.in);
  System.out.println("Enter a Number");
  int num = sc.nextInt();
         System.out.println(num);
  if(num == 1)
  {
   System.out.print(num+" is Not Prime");
   return;
  }
  else
  {
   for(i=2;i<num;i++)
   {
    if(num%2==0)
    {
     count++;
    }
   }
   if(count>1)
   {
    System.out.print(num+" is Not Prime");
   }
   else
   {
    System.out.print(num+" prime number");
   }
  }
 }
}
2. Binary Search
Code:
import java.util.Scanner;
public class binarySearch 
{
  @SuppressWarnings("resource")
  public static void main(String args[]) 
  {
 Scanner sc = new Scanner(System.in);
 int num,size,mid;
 System.out.println("Enter Array size ");
 size=sc.nextInt();
 int arr[]=new int[size];
 System.out.println("Enter Array elements in ascending order ");
 for (int i = 0; i < size; i++) 
 {
          arr[i]=sc.nextInt();
 }  
 System.out.println("Enter Search key ");
 mid=size/2;
 num = sc.nextInt();
 for (int i = 0; i < size; i++) 
 {
   for (int j = size-1; j >=mid+1; j--) 
   {
    if (num == arr[mid]) 
    {
     mid=arr[mid];
    }
    else
    {
  //you try this☺
    }    
 }   
     }
    System.out.println("Element "+num+" found in index "+mid);
  }
}
3. Java Program to Reverse a given String
Code:
import java.util.Scanner;
@SuppressWarnings("resource")
public class reverseString 
{
  public static void  main(String args[]) {
     Scanner sc = new Scanner(System.in);
  System.out.println("Enter a String");
  String str = sc.next();
  String rev = " ";
  for (int i = str.length()-1; i>=0; i--) 
  {
 rev = rev+str.charAt(i);  
  }
  System.out.println("Original String "+str+" Reversed String is "+rev);
  if(str.equalsIgnoreCase(rev))
  {
 System.out.println("Palindrome ");
  }
  else
  {
   System.out.println("Not Palindrome");
  }
 }
}
4. Java Program to find Largest in an Array
Code:
public class largeInArray 
{
 public static void main(String args[]) 
 {
 int arr[]= {1,5,0,-1,10,15,7};
 int large=0;
 for(int i=0;i<arr.length;i++)
 {
  if(arr[i] > large)
  {
  large = arr[i];
  }
 }
 System.out.println(large);
  } 
}
5. Armstrong Number
Code:
public class armstrongNum 
{
 public static void main(String[] args)  
 {  
    int c=0,a,temp;  
    int n=153;//It is the number to check Armstrong  
    temp=n;  
    while(n>0)  
    {  
    a=n%10;  
    n=n/10;  
    c=c+(a*a*a);  
    }  
    if(temp==c)  
    System.out.println("armstrong number");   
    else  
        System.out.println("Not armstrong number");   
   }  
}
6. Program on static operations
class A
{
 static int x;
 int y;
 A(int a,int b)
 {
  x=a+b;
  y=x+b;
 }
}
public class StaticOperations 
{
 @SuppressWarnings("static-access")
 public static void main(String args[]) 
 {
  A a=new A(2,3);
  A a1=new A(5,10);
  System.out.println(a.x+" "+a.y);  
 }
}
 

 









