program main

	Integer*2   i2,I2BigToLittle
	Integer*4   i4,I4BigToLittle
	Real*4      r4,R4BigToLittle
	Real*8      r8,R8BigToLittle
        Character   C4*4, C8*8, c16*16

* 設定各變數的初值
	i2=10
	i4=10
	r4=10.
	r8=10.
	
* 使用 Big <-> little 函數的互轉範例
	write(*,*) i2,I2BigToLittle(i2),I2BigToLittle(I2BigToLittle(i2))
	write(*,*) i4,I4BigToLittle(i4),I4BigToLittle(I4BigToLittle(i4))
	write(*,*) r4,R4BigToLittle(r4),R4BigToLittle(R4BigToLittle(R4))
	write(*,*) r8,R8BigToLittle(r8),R8BigToLittle(R8BigToLittle(r8))

* 使用 Big <-> little 逐步執行的互轉範例
	write(c4,'(z4)') i2
	write(*,*) c4
	call BigToLittle(c4) 
	read(c4,'(z)') i2
	write(*,*) c4,i2
	call BigToLittle(c4) 
	read(c4,'(z)') i2
	write(*,*) c4,i2

	write(c8,'(z8)') i4
	write(*,*) c8
	call BigToLittle(c8) 
	read(c8,'(z)') i4
	write(*,*) c8,i4
	call BigToLittle(c8) 
	read(c8,'(z)') i4
	write(*,*) c8,i4

	write(c8,'(z8)') r4
	call BigToLittle(c8) 
	read(c8,'(z)') r4
	write(*,*) c8,r4
	call BigToLittle(c8) 
	read(c8,'(z)') r4
	write(*,*) c8,r4

	write(c16,'(z16)') r8
	call BigToLittle(c16) 
	read(c16,'(z)') r8
	write(*,*) c16,r8
	call BigToLittle(c16) 
	read(c16,'(z)') r8
	write(*,*) c16,r8

	end program

	Integer*2 Function I2BigToLittle(i2)

	Integer*2   i2,ti2
        Character   c4*4

	write(c4,'(z4)') i2
	call BigToLittle(c4) 
	read(c4,'(z)') ti2
	I2BigToLittle=ti2

	end function

	Integer*4 Function I4BigToLittle(i4)

	Integer*4   i4,ti4
        Character   c8*8

	write(c8,'(z8)') i4
	call BigToLittle(c8) 
	read(c8,'(z)') ti4
	I4BigToLittle=ti4

	end function

	Real*4 Function R4BigToLittle(r4)

	Real*4      r4,tr4
        Character   c8*8

	write(c8,'(z8)') r4
	call BigToLittle(c8)
	read(c8,'(z)') tr4
	R4BigToLittle=tr4

	end function

	Real*8 Function R8BigToLittle(r8)

	Real*8      r8,tr8
        Character   c16*16

	write(c16,'(z16)') r8
	call BigToLittle(c16)
	read(c16,'(z)') tr8
	R8BigToLittle=tr8

	end function

	Subroutine BigToLittle(Hex)

	Character*(*) Hex
	Integer*4 i,tLen
	
	tLen=len(Hex)

	do i=1,tLen
	   if (Hex(i:i) .eq. ' ') then
	      Hex(i:i)='0'
		end if
	end do

	do i=1,tLen/2,2
	   call SwapChar(Hex(i:i+1),Hex((tLen-i):(tLen-i+1)))
	end do

        end Subroutine

	Subroutine SwapChar(Char1,Char2)

	Character*(*)  Char1, Char2
	Character*1024 tChar

	tChar=Char1
        Char1=Char2
	Char2=tChar

	end Subroutine