I've read the arithmetic method somewhere, I can't remember where.

Every better (basic) method of swapping is welcome, don't hesitate to post it, I'll be happy to add it to my small collection.

Code: Select all

```
'SWAP.BAS LBB 17-01-2018
'========
x = 2
y = 3
PRINT "let x = "; x
PRINT "let y = "; y
PRINT
'--- arithmetic method
PRINT "--- Swapping 10001 times x and y by an arithmetic method"
PRINT
t1 = TIME$("ms")
FOR n = 1 TO 10001 'must be ODD !
x = x + y
y = x - y ' ' ' i.e. x + y - y = x
x = x - y ' ' ' i.e. x - x + y = y
NEXT n
t2 = TIME$("ms")
PRINT "time = "; t2 - t1; " msec"
PRINT "now x = "; x
PRINT "now y = "; y
PRINT
'--- with an intermediate variable< tmp>
PRINT "--- Swapping 10001 times x and y with a temporary variable"
PRINT
t1 = TIME$("ms")
FOR n = 1 TO 10001
tmp = x
x = y
y = tmp
NEXT n
t2 = TIME$("ms")
PRINT "time = "; t2 - t1; " msec"
PRINT "now x = "; x
PRINT "now y = "; y
PRINT
'--- using the extra-keyword < ! SWAP >
PRINT "--- Swapping 10001 times x and y with the extra-keyword < !SWAP >"
PRINT
t1 = TIME$("ms")
FOR n = 1 TO 10001
! SWAP x, y
NEXT n
t2 = TIME$("ms")
PRINT "time = "; t2 - t1; " msec"
PRINT "now x = "; x
PRINT "now y = "; y
PRINT
'--- Terminate
PRINT "ENTER/RETURN to terminate...";
INPUT enter$
!QUIT
END
```