BlablaJava

import java.util.Scanner;
import java.lang.*;
public class EX_01{

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		//EX_01
		{

			int arr[] = new int[3];
			Scanner sc = new Scanner(System.in);
			System.out.println("Hello!\nPlease enter 3 numbers:");

			for(int i=0;i<3;i++)
			{
				arr[i]=sc.nextInt();
			}

			int pow1=arr[0]*arr[0], pow2=arr[1]*arr[1], pow3=arr[2]*arr[2];

			if (pow1==pow2+pow3||pow2==pow1+pow3||pow3==pow1+pow2)
			{
				System.out.println("Pythagorean triplet!");
			}
			else
			{
				System.out.println("NO!");
			}
		}

		//EX_02
		{
			int num,print=1,counter=0;
			System.out.println("\nHello!\nPlease enter a number (bigger then 1):");
			Scanner sc = new Scanner(System.in);
			num= sc.nextInt();

			for (int i=0;i<num*num;i++)
			{
					System.out.print(print+"\t");
					print++;
					counter++;
					if (counter==num)
					{
						counter=0;
						System.out.println();
					}
			}
		}

		//EX_03
		{
			System.out.println("\nHello!\nPlease give me a string:");
			Scanner sc= new Scanner(System.in);
			String str= sc.nextLine();
			int begin=0, end=str.length()-1;

			while(begin<end)
			{
				if (str.charAt(begin)!=str.charAt(end))
				{
					System.out.println("Not a palindrome!");
					break;
				}
				begin++;
				end--;
			}

			if (begin==end)
			{
				System.out.println("Palindrome with middle!");
			}
			if (begin>end)
			{
				System.out.println("Palindrome without middle!");
			}
		}

		//EX_04
		{
			int num, counter=0;
			float sum=0;
			Scanner sc= new Scanner(System.in);
			System.out.println("\nHello!\nPlease enter a size for the array: ");
			num=sc.nextInt();
			int[] arr= new int[num];
			System.out.println("Please enter " + num + " numbers to the array:");

			for (int i=0;i<num;i++)
			{
				arr[i]=sc.nextInt();

				if (arr[i]%2==0)
				{
					sum+=arr[i];
					counter++;
				}
			}
			System.out.println("The avarage of the even numbers in the array is: " + sum/counter);
		}

		//EX_05
		{
			int[][] arr;
			int num,sum=0;
			Scanner sc = new Scanner(System.in);
			System.out.println("\nHello!\nPlease enter a number: ");
			num= sc.nextInt();
			arr= new int[num][num];

			System.out.println("The Matrix is:");

			for(int i=0;i<num;i++)
			{
				for(int j=0;j<num;j++)
				{
					arr[i][j]=(int) (Math.random()*100+1);
					System.out.print(arr[i][j]+ "\t");
					if(i==j)
					{
						sum+=arr[i][j];
					}
				}
				System.out.println();
			}
			System.out.println("\nThe Sum of the main diagonal is: " + sum);
		}
	}
}


/*
------OUTPUT EXAMPLE------
Hello!
Please enter 3 numbers:
5
3
4
Pythagorean triplet!

Hello!
Please enter a number (bigger then 1):
3
1	2	3
4	5	6
7	8	9

Hello!
Please give me a string:
BlalB
Palindrome with middle!

Hello!
Please enter a size for the array:
4
Please enter 4 numbers to the array:
3
5
6
6
The avarage of the even numbers in the array is: 6.0

Hello!
Please enter a number:
4
The Matrix is:
31	28	82	21
98	54	52	12
15	57	46	27
22	60	48	80

The Sum of the main diagonal is: 211

-------------------------------------------------------------

*/