How to swap two variables values without using a third variable?

[ReneMiner]

just do some math:

Uses "Console"

Double a = 1.234
Double b = 5.678

console_writeLine("A = " + str$(a) )
console_writeLine("B = " + str$(b) )

a += b
b = a - b
a = a - b

console_writeLine("A = " + str$(a) )
console_writeLine("B = " + str$(b) )

console_waitKey()

How about Strings?

Uses "Console"

String A = "World !"
String B = "Hello "

Console_WriteLine(A + B)

A += B
B = Left$( A, Len(A) - Len(B) )
A = Right$(A, Len(A) - Len(B) )

console_writeLine(A + B)

console_waitKey()

or in thinBasic:

'...
Swap A,B
'...