Structures

      program loops

      implicit none
      integer i, num_intervals
      real PI, TwoPi, w,z,size
      real x(11), y(11)
      Parameter(PI=3.141592653)

      open(1,file='data',type='unknown')
      read(1,*)num_intervals
      close(1)

c      do 10 i = 1,num_intervals
c        write(*,*) i
c   10 continue

      do i = 1, num_intervals
        size=1.0/(num_intervals-1.0)
        x(i)=(i-1)*size
        write(*,*) x(i)
      end do

      write(*,100)
      read(*,*) num_intervals

      TwoPi = 2 * Pi
      do i = 1,num_intervals
         w = TwoPi / num_intervals * i
         z = sin(w)
         write(1,110) w,z
      end do

  100 format('Please input the number of intervals: ',$)
  110 format(F10.2,F9.3)

       write(*,200)
       Read(*,*) z
       If (z .LT. 0) Then
          write(*,*) z, 'is a negative number'
       elseif (z .GT. 0) Then
          write(*,*) z, 'is a positive number'
       else
          write(*,*) 'z is 0'
       endif
  200  format('Please input a number: ',$)

      end