program cch
implicit none

real theta, pi/3.141592/, r, x, y
real length/1./
real dum, x0, y0
real c/0./

 theta = pi/200.
 r = length/sin(theta)
 print *, " length =", length, "r = ",r, " theta = ", theta
 do dum = 0,theta,theta/100.
   x=r*sin(dum)
   y= r*(1-cos(dum))
    write(11,'(3e12.4)')dum,x,y
   x0=x
   y0=y
 end do
c = c + r*theta
print *, x0, y0, c
 x0 = x0+length
 y0 = y0+length*tan(theta)
  c = c + length/cos(theta)
print *, x0, y0, c
 do dum =  -theta,theta, theta/100.
  y = y0 +r*(-cos(theta)+cos(dum))
  x = x0+ r*sin(theta+sin(dum))
   write(11,'(3e12.4)')dum,x,y
 end do
 c = c + 2*r * theta
print *, x,y, c
 x0= x+length
 y0 = y - length * tan(theta)
 c = c + length/cos(theta)
print *, x0,y0,c
 do dum = theta,0,-theta/100
  y = r*(1-cos(dum))
  x = x0+r*(sin(theta) - sin(dum))
  write(11,'(3e12.4)')dum,x,y
 end do
 c = c + r * theta
print *, x, y, c, c-6*length
print '(a,e12.4)',' Change in cirumference for 6 wavelength chicahne = ', 6*(c-6*length)
end