Dex-TS

PART I - Intro & TOC

Dex-TS

About

Dex-TS is an open-source Tri-Stack Calculator (math expression parser) written in C++ using STL with good OOP design patterns. It is the official successor to C-Flat. Dex-TS has been rewritten from scratch and is now a distributable DLL. I am releasing it in response to UCALC and USPExpress, two excellent pieces of code that have unfortunately gone commercial.

System Requirements

• WinXP / WinNT / Win2000 / WinMe / Win98 / Win95

Download

If your system meets the requirements stated above, you may download Dex-TS here (with source).

(note: this program is provided AS IS without warranty of any kind.. etc etc)

Algorithm

This example demonstrates the basics of Tri-Stack. The three stacks (opStack, elemStack, and inStack) are denoted here as [O], [E], and [I]. A sequence of pushes and pops computes the solution.

"1 * 2 + 3"

Step 1 (Format)

Add parenthesis around expression.

• "(1 * 2 + 3)"

Step 2 (Group)

Group tokens into operators and operands.

• [O]: ( * + )
• [E]: 1 2 3
• [I]:

Force top-most opStack operator into inStack (to start chain reaction).

• [O]: ( * +
• [E]: 1 2 3
• [I]: )

Step 3 (Load)

Load inStack with opStack, elemStack elements

(stop when inStack top-most operator ranks higher than opStack top-most operator)

• [O]: (
• [E]: 1
• [I]: ) 3 + 2 *

Step 5 (Bind)

Force inStack top-most operator into opStack.

• [O]: ( *
• [E]: 1
• [I]: ) 3 + 2

Bind elemStack, inStack operands with an opStack operator (push result back into inStack).

1 * 2 = 2

• [O]: ( *
• [E]: 1
• [I]: ) 3 + 2

2 + 3 = 5

• [O]: ( +
• [E]: 2
• [I]: ) 3

Remove extra parenthesis in opStack, inStack.

• [O]: (
• [E]: 5
• [I]: )

Return remaining elemStack operand if inStack empty, goto Step 3 if otherwise.

• [O]:
• [E]: 5
• [I]:

Table of Contents

1. Intro & TOC

Next: EOF (aka no more)

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