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Manual Reference Pages  - isobj (3)

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NAME

isobj(3f) - [M_draw:OBJECT] Returns .FALSE. if there is an object of number n. (LICENSE:PD)

CONTENTS

Synopsis
Description
Example

SYNOPSIS

logical function isobj(n) integer :: n

DESCRIPTION

Returns .FALSE. if there is an object of number n.

EXAMPLE

Sample program:

   program demo_isobj
   use M_draw
      call prefsize(300, 300)
      call prefposition(100, 100)
      call vinit(’ ’)   ! set up device
      call ortho2(-5.0,5.0,-5.0,5.0)
      call color(D_WHITE)  ! set current color
      call clear()   ! clear screen to current color

      call makeobj(3)  ! create a simple object
         call polyfill(.true.)
         call color(D_GREEN)
         call circle(0.0,0.0,4.0)
      call closeobj()

      if(isobj(3))then
         write(*,*)’ 3 is an object (CORRECT)’
         call callobj(3)
      else
         write(*,*)’ 3 is not an object (ERROR)’
      endif

      if(isobj(4))then
         write(*,*)’ 4 is an object (ERROR)’
      else
         write(*,*)’ 4 is not an object (CORRECT)’
      endif

      call callobj(4) ! note: calling a non-existent object is a no-op

      idum=getkey()! wait for some input
      call vexit()!  set the screen back to its original state

   end program demo_isobj

Expected output:

3 is an object (CORRECT) 4 is not an object (CORRECT)

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isobj (3)

March 11, 2021

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