Two Dimensional Array in Java Part – 1

Program 1

import java.util.*;
class TestTwoDArray
{
     public static void main(String args[])  
     {
          int r,c,m,n;
          Scanner scan=new Scanner(System.in);
          System.out.println("Enter values of row and column");
          m=scan.nextInt();
          n=scan.nextInt();

            int ar[][]=new int[m][n];
      
            System.out.println("Enter elements in matrix");
            for(r=0;r<m;r++)  //outer loop for row
            {
                for(c=0;c<n;c++) //inner loop for row
                { 
                   ar[r][c]=scan.nextInt();
                }  
            }
            System.out.println("-------Elements if matrix----------");
             for(r=0;r<m;r++)  //outer loop for row
            {
                for(c=0;c<n;c++) //inner loop for row
                {
                  System.out.print(ar[r][c] + "   ");
                }
                  System.out.println();
            }

           if(m==n) 
          { 
             System.out.println(".....Upper Triangle elements....");
            for(r=0;r<m;r++)  //outer loop for row
            {
                for(c=0;c<n;c++) //inner loop for row
                {
                    if(r<=c)
                     System.out.print(ar[r][c] + "   ");
                }
                  System.out.println();
            }
         }
         else
         System.out.println("Invalid mtrix for triangle elements.");


          if(m==n)
          { 
             System.out.println(".....Lower Triangle elements....");
            for(r=0;r<m;r++)  //outer loop for row
            {
                for(c=0;c<n;c++) //inner loop for row
                {
                    if(r>=c)
                     System.out.print(ar[r][c] + "   ");
                }
                  System.out.println();
            }
         }
         else
         System.out.println("Invalid mtrix for triangle elements.");

             if(m==n)
          { 
             System.out.println(".....Digonal elements....");
               for(int i=0;i<m;i++)
                 System.out.println(ar[i][i]);

            // for(r=0;r<m;r++)  //outer loop for row
            // {
            //     for(c=0;c<n;c++) //inner loop for row
            //     {
            //         if(r==c)
            //          System.out.print(ar[r][c] + "   ");
            //     }
            //       System.out.println();
            // }
         }
         else
         System.out.println("Invalid mtrix for digonal elements.");

     }
}