Re: implementing a stack
- To: mathgroup at smc.vnet.net
- Subject: [mg16409] Re: implementing a stack
- From: Guilherme Roschke <gr at network3.entropy.upenn.edu>
- Date: Thu, 11 Mar 1999 02:17:08 -0500
- Organization: University of Pennsylvania
- References: <7ag29l$agg@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Will Self wrote: > > I would like to implement a simple stack in Mathematica. > I can use PrependTo for "push", but in that case how do > I implement "pop"? I have thought about this and I see > that I can do it by creating a global variable that keeps > a list of pairs: the symbols that serve as the names > of the stacks, and the stacks themselves; and having pop > and push access and manipulate this list. Is that really > what I have to do? > > Explicitly, > push[a, 1] should push the number 1 onto the stack a, and > return nothing, > and > pop[a] should return whatever is on the top of stack a, and > reset a to be the rest of the stack. > > Will Self Use List functions: First[list] returns the first element of a list Rest[list] returns the list minus the first element. have fun. -- Guilherme Roschke Programmer Dept. of Anesthesia University of Pennsylvania Medical School gr at network3.entropy.upenn.edu