Square Matrix II

#include<stdio.h>
int main()
{
    int i,j,n,a,b;
    while(1)
    {
        scanf("%d",&n);
        if(n==0)
            break;

        int arr[n][n];

        for(i=0; i<n; i++)
        {
            a=i+1;
            b=2;
            for(j=0; j<=i; j++,a--)
            {
                arr[i][j]=a;
            }
            for(j=i+1; j<n; j++,b++)
            {
                arr[i][j]=b;
            }
        }

        for(i=0; i<n; i++)
        {
            for(j=0; j<n; j++)
            {
                if(j==0)
                {
                    printf("%3d",arr[i][j]);
                }
                else
                    printf(" %3d",arr[i][j]);
            }
            printf("\n");
        }
        printf("\n");
    }

    return 0;
}