rosetta-code-compiler-forth/tests/input/mandelbrot.in

{
/*
 This is an integer ascii Mandelbrot generator
 */
    left_edge   = -420;
    right_edge  =  300;
    top_edge    =  300;
    bottom_edge = -300;
    x_step      =    7;
    y_step      =   15;
 
    max_iter    =  200;
 
    y0 = top_edge;
    while (y0 > bottom_edge) {
        x0 = left_edge;
        while (x0 < right_edge) {
            y = 0;
            x = 0;
            the_char = ' ';
            i = 0;
            while (i < max_iter) {
                x_x = (x * x) / 200;
                y_y = (y * y) / 200;
                if (x_x + y_y > 800 ) {
                    the_char = '0' + i;
                    if (i > 9) {
                        the_char = '@';
                    }
                    i = max_iter;
                }
                y = x * y / 100 + y0;
                x = x_x - y_y + x0;
                i = i + 1;
            }
            putc(the_char);
            x0 = x0 + x_step;
        }
        putc('\n');
        y0 = y0 - y_step;
    }
}