PET VIC-20 C64 C16 Plus/4 C128 X16 M65

The SWAP command is used to exchange the values of two variables.

SWAP <left>, <right>

After the operation, the variable left will have the value of right and vice versa.

The SWAP command is especially useful in sorting algorithms:

REM -- Bubble sort 10 random long numbers --

CONST TRUE = 255
CONST FALSE = 0

DIM nums(10) AS LONG
DIM swapped AS BYTE FAST
DIM i AS BYTE FAST
DIM j AS BYTE FAST

RANDOMIZE TI()
FOR i = 0 TO 9 : nums(i) = RNDL() : NEXT

swapped = FALSE
FOR i = 0 TO 8
    FOR j = 0 TO 8 - i
        IF nums(j) > nums(j + 1) THEN
          SWAP nums(j), nums(j + 1)
          swapped = TRUE
        END IF
    NEXT j
    IF swapped = FALSE THEN EXIT FOR
NEXT i

FOR i = 1 TO 9 : PRINT nums(i) : NEXT