// while we're less than or equal to the number of iterations
    for(itt=0; itt<=itt_max; itt++)
    {
        // reset error
        error=0.0;

        // rows
        for(i=0; i< n; i++)
        {
            sum = 0.0;

            // columns of the rows
            for(j=0; j< n; j++)
            {
                // multiply an entry
                sum += a[i][j] * t[j];
            }

            t1[i] = sum + b[i];
            errori = fabs(t1[i]-t[i]);
            if(errori > error) {
                error=errori;
            }
        }

        // answer into temporary array
        ttemp = t1;

        // old x vector into t1 (why?)
        t1 = t;

        // new x vector is the answer from the last multiplication
        t = ttemp;

        // print, do it all over again
        printf("%5d %14.6e\n", itt, error);
    }