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I hope things are going well. I am doing some recursion stuff with databases and the text book I am reading has made it clear there is a difference between n-1 for example and n - 1. The difference being there is spacing. I know n-1 means n minus one. Does anyone know what the other is. Maybe n to one or n in increments of one.

Thanks in advance.

Ben.

Gerry Myerson
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user133149
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    Technically it's the same. Perhaps a little more context would help us give you an answer. How does the book make it clear they are different? – user88595 Jun 29 '14 at 08:10
  • The subtraction operation can also be conveyed by the term "difference" may be something else to note here. – JB King Jun 29 '14 at 08:14
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    What database language are you using? SQL? Perhaps the language you are using implements some sort of implicit parenthesis based on the spacings in the expression. – Yiyuan Lee Jun 29 '14 at 08:15
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    Perhaps they mean the difference between $u_{n+1}=u_{n-1}$ and $u_{n+1}=u_{n}-1$? – Pim Jun 29 '14 at 08:18
  • I have to snippets from the textbook, points at which the distinction was made, 1, "The constructor set size to 0 and front to 0 because array element theData[0] is considered the front of the empty queue, and rear is initialized to capacity - 1(instead of -1)" 2, "Increments the subscript for array theData. Therefore, subscript j goes from the capacity - 1 (in increments of 1) and then back to zero" Its actually to do with data structures not database languages my bad. Java specifically. Sorry I don't think I can really give any more context without handing you the text book :3 – user133149 Jun 29 '14 at 08:27
  • I have sent an E-mail to my lecturer and will update you guys on proceedings. – user133149 Jun 29 '14 at 08:44
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    It seems the dsitnction is between $\text{capacity}-1$ (one less than the capacity) and $-1$ (the number below zero). Indeen the typeset spacing is different within a difference $n-1$ and when used as unary sign, $-1$. – Hagen von Eitzen Jun 29 '14 at 09:04

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