Addition of two matrices/matrix

/****************************
*  Umang B Bhatt       *
*   bhatt.umang7@gmail.com  *
*****************************/

/**
 * program for addition of matrices
 */
#include<stdio.h>
void main()
{

 int ar = 0 , ac = 0 , i = 0 , j = 0 , br = 0 , bc = 0 ;

 int a[20][20] , b[20][20] , ans[20][20];

 // scan the first array
 printf("Enter no of rows in first matrix ? ");
 scanf("%d",&ar);

 printf("Enter no of columns in first matrix ? ");
 scanf("%d",&ac);
 if(ar < 0 || ar>20 || ac < 0 || ac>20)
 {

  printf("Invalid number of rows or columns. It must be brtween 1 to 20");
 }
 else
 {
  // logic for scanning the numbers
  for(i = 0 ; i < ar ;i++)
  {

   for(j = 0 ; j < ac ; j++)
   {

    printf("Enter element [%d][%d]: ", i,j);
    scanf("%d",&a[i][j]);
   }
  }

  printf("Enter no of rows in second matrix ? ");
  scanf("%d",&br);
  printf("Enter no of columns in second matrix ? ");

  scanf("%d",&bc);

  // scan the second array
  if(br < 0 || br>20 || bc < 0 || bc>20)
  {

   printf("Invalid number of rows or columns. It must be brtween 1 to 20");
  }
  else
  {
   // logic for scanning the numbers
   for(i = 0 ; i < br ;i++)
   {

    for(j = 0 ; j < bc ; j++)
    {

     printf("Enter element [%d][%d]: ", i,j);
     scanf("%d",&b[i][j]);
    }
   }

   if((ar == br ) && (ac == bc))
   {

    for( i = 0 ; i < ar ; i++)
    {

     for(j = 0 ; j < ac ; j++)
     {

      ans[i][j] = a[i][j] + b[i][j];
     }
    }

    printf("\nAddition of marices is:\n");
    for(i = 0 ; i < ar ; i++)
    {

     for(j = 0 ; j < ac ; j++)
     {

      printf( "%d \t" , ans[i][j]);
     }
     printf("\n");
    }
   }

   else
   {
    printf("\nNo of rows does not match no of columns. So addition is not possible");
   }
  }
 }
}