Swapping a digit and printing highest possible subset of 1's in a array containing 0's and 1's

hackers-with-bits.c

//Author: Harshvardhan Karn
#include <stdio.h>

main()
{
   int a[100],n,i=0,counter=0,z=0,countfwd=0,countbwd=0,max=0,maxpos=0,countedtill=0, maxswap = 0, onecounter = 0;
    //taking size of array
   scanf("%d",&n);
   //taking input for array
   for(i=0;i<n;i++)
   {
   scanf("%d",&a[i]);
   }
   //searching for sub array
    while(counter<n) //run till array ends
    {
      if (a[counter] == 0 ) //when zero encounters take it as a point and then
      {    //Forwards
          if(counter < n && a[counter+1] == 1) // run forward if next to it is 1
          {
              z=counter+1; //forward 1th position stored in z
              while(a[z] == 1 && z <= n)
              {
               countfwd++;
               z++;  //z is current position
              }
              if(countfwd > max )
              {
                  max = countfwd;
                  maxpos = z;
                  //countfwd = 0;
                  countedtill = z;
              }

          }

          //backwards
          if(a[counter-1] == 1 && counter > 0) // run backwards if next to it is 1
          {
              z=counter-1; //backwards 1th position stored in z
              while(a[z] == 1 && z >= 0 )
              {
               countbwd++;
               z--;  //z is current position
              }
              if(countbwd > max )
              {
                  max = countbwd;
                  maxpos = counter;
                  countedtill = z;
                  //countbwd = 0;
              }
          }
        if(a[counter+1] == a[counter-1])
        {
            if(max<(countfwd+countbwd))
            {
                max = countfwd+countbwd;
            }
        }
      countfwd = countbwd = 0;
      
      }
else //it will execute when there are only 1 in array
      {
          onecounter++;
      }
    counter++;
    }
    if(max == 0)
    {
        if(onecounter == n)
        {
            maxswap = n;
        }
        else
        {
         maxswap= max;
        }

    }
    else if(max == onecounter) //if there is no remaining 1 other than the found in subset, to swap
    {
        maxswap = max;

    }
    else
    {
        maxswap = max + 1; // +1 because swapping will done here after
    }
    printf("%d ", maxswap);

   return 0;
}