c     program     :     SWAP_BYTE_CPC_UNI_GAG_ANAL.lnx.f
c     objective   :     sample program to swap the byte order from little_endian 
c                       to big_endian for the CPC Unified Daily Gauge Analysis 
c
      parameter  ( kyy = 2006, kmm = 12, kdd = 31 ) 
c 
      parameter  ( nx = 720, ny = 360 ) 
c
c
      character  cdate*8, cfile10*47, cfile50*47, 
     #           cinp*2880, cout*2880 
c
c     1.  to open the input / output data files 
c 
      kdate = kyy*10000 + kmm*100 + kdd 
      write  (cdate,1951)  kdate 
 1951 format  (i8) 
      write  (6,*)  'started swapping bytes for :  ', cdate 
c
      cfile10 ( 1: 4) = 'yyyy' 
      cfile10 ( 5:47) = '/PRCP_CU_GAUGE_V1.0GLB_0.50deg.lnx.yyyymmdd'
      cfile50 ( 1: 4) = 'yyyy'
      cfile50 ( 5:47) = '/PRCP_CU_GAUGE_V1.0GLB_0.50deg.sgi.yyyymmdd'
      cfile10 ( 1: 4) = cdate (1:4) 
      cfile10 (40:47) = cdate (1:8) 
      cfile50 ( 1: 4) = cdate (1:4)
      cfile50 (40:47) = cdate (1:8)
c
      open  (unit=10, 
     #       file=cfile10, 
     #       access='direct', recl=nx*4) 
      open  (unit=50, 
     #       file=cfile50, 
     #       access='direct', recl=nx*4) 
      write  (6,*)  'finished opening data files !!' 
c
c     2.  to convert 
c 
      do 2002 kk = 1, 2  
      do 2002 jj = 1, ny 
        krec = (kk-1)*ny + jj  
        read  (10,rec=krec)  cinp 
        do 2001 ii = 1, nx 
          i1 = (ii-1)*4 + 1  
          i2 = (ii-1)*4 + 2  
          i3 = (ii-1)*4 + 3  
          i4 = (ii-1)*4 + 4  
          cout (i1:i1) = cinp (i4:i4)  
          cout (i2:i2) = cinp (i3:i3)  
          cout (i3:i3) = cinp (i2:i2)  
          cout (i4:i4) = cinp (i1:i1)  
 2001   continue 
        write  (50,rec=krec)  cout 
 2002 continue 
      write  (6,*)  'finished swapping byte order !!' 
c
c 
      stop 
      end