program Koch implicit none integer pgopen,n,big_small character*10 string write(*,*) 'Big window or small (2 = big ; 1 = small) :' read (*,*) big_small c if (big_small.eq.1) big_small = big_small*2 write(*,*) 'How many levels to draw ?' read (*,*) n c write(string,'(i2)') n ! This will also works. write(string,100) n 100 format (i2) string = 'n ='//string if (pgopen('/xwin').le.0) stop call pgpap(6.0*big_small,0.5) call pgenv(0.0,1.0,0.0,0.3,1,-2) call pgsch(2.0) call pglab(string,'','Koch curve') call draw_koch( (0.0,0.0), (1.0,0.0), n) call pgclos end subroutine draw_koch (z1,z2,n) implicit none integer n,n1,n2,n3,n4 complex z1,z2,za,zb,zc,dz,phase real length,pi_3,x(2),y(2) parameter (pi_3=3.14159268/3.0) if (n.gt.0) then n = n - 1 n1 = n n2 = n n3 = n n4 = n c write(*,*) 'The new n is : ',n dz = (z2-z1)/3 za = z1 + dz zc = z1 + 2*dz phase = (1.0,0.0)*cos(pi_3) + (0.0,1.0)*sin(pi_3) zb = za + dz*phase call draw_koch (z1,za,n1) call draw_koch (za,zb,n2) call draw_koch (zb,zc,n3) call draw_koch (zc,z2,n4) else x(1) = real(z1) x(2) = real(z2) y(1) = imag(z1) y(2) = imag(z2) call pgline (2,x,y) c write(*,*) 'A line has been drawn between', z1,' and ',z2 endif end