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Discussion on: How can you swap two variables without using a third?

 
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Theofanis Despoudis

That's the second step in becoming a computer scientist.

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Lewis Cowles

limit x and y to 16 bit or store 32-bit numbers in 64-bit. max int for 64-bit signed or unsigned is twice that of it's 32-bit counterpart.

You cannot overcome size problem if it's expressed in bits. Only higher-order structures like arrays would enable that and then you are absolutely storing more than two variables (possibly more than one per entry if it's a pointer).

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theodesp profile image
Theofanis Despoudis • Edited

That defeats the purpose of doing that plus you are making a difficult work of complicating things. I suspect is better if you use a temp variable after all!

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lewiscowles1986 profile image
Lewis Cowles

I suspect it's better if you don't try to copy with only two memory areas, but if you're going to worry about overflowing, then doubling storage size is the least complex thing you could do, and compatible with various CPU operating modes.