Table of Contents

SWAP

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

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

Syntax

SWAP <left>, <right>

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

Warning

The two variables can be of any type, but their types must be the same.

Example

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