Матрица

//https://otvet.mail.ru/question/211343438

#include <stdio.h>

#define NINE 9

int main()
{
   int i,j,counter,gap,top=0;
   int arr3[NINE][NINE]={0};
   counter = gap = 1;

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

       for(i=gap;i<NINE-gap;i++)
       {
           arr3[i][j]=counter++;
       }



        if(top||gap==5)//gap decreases from now on
        gap--,top++;
        else if(gap<5)//gap increases here
        gap++;


   }
   for(i=0;i<NINE;i++)
   {
       for(j=0;j<NINE;j++)
        printf("%4d",arr3[i][j]);
       printf("\n");
   }

    return 0;
}