Entry
Language: Computer: C#: Simple: How to convert infix to suffix? [Bracket]
Jan 10th, 2004 14:27
Knud van Eeden,
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--- Knud van Eeden --- 10 January 2004 - 08:00 pm --------------------
Language: Computer: C#: Simple: How to convert infix to suffix?
[Bracket]
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Steps: Overview:
1. -Create a new C# application
2. -Fill in the following code
--- cut here ---------------------------------------------------------
namespace ConsoleApplication3 {
using System;
//
class CLASSStringConvertInfixToSuffix {
private string expressionS;
private string tabletokenS;
private string tableinputS;
private string tablestackS;
private string stackS;
private string kexpressionS;
private string kstackS;
private string resultS;
private int expressionI;
private int stackI;
private int posI;
private int priorityinputI;
private int prioritystackI;
private int I;
// constructor for this class
public CLASSStringConvertInfixToSuffix( string expressionS )
{
this.expressionS = expressionS;
tabletokenS = "#-+*/^abcdefghijklmnopqrstuvwxyz0123456789()";
tableinputS = "03344599999999999999999999999999999999999992";
tablestackS = "03344599999999999999999999999999999999999929";
stackS = "";
kexpressionS = "";
kstackS = "";
resultS = "";
expressionI = 0 - 1;
stackI = 0 - 1;
posI = -1;
priorityinputI = -1;
prioritystackI = -1;
I = 0;
stackI = stackI + 1;
stackS = "#";
}
// destructor for this class
~CLASSStringConvertInfixToSuffix() {
}
public string FNStringConvertInfixToPrefixS() {
do
{
expressionI = expressionI + 1;
kexpressionS = expressionS.Substring( expressionI, 1 );
posI = tabletokenS.IndexOf( kexpressionS, 0 );
if ( posI == -1 ) {
Console.WriteLine( kexpressionS + " not found in tabletokenS " +
tabletokenS );
return( "error" );
}
priorityinputI = int.Parse( tableinputS.Substring( posI, 1 ) );
kstackS = stackS.Substring( 0, 1 );
posI = tabletokenS.IndexOf( kstackS, 0 );
if ( posI < 0 ) {
Console.WriteLine( kstackS + " not found in tabletokenS " +
tabletokenS );
return( "error" );
}
prioritystackI = int.Parse( tablestackS.Substring( posI, 1 ) );
if ( priorityinputI > prioritystackI ) {
stackS = kexpressionS + stackS;
}
else {
do {
if ( ( kstackS != "(" ) && ( kstackS != ")" ) ) {
resultS = resultS + kstackS;
}
stackS = stackS.Substring( 1, stackS.Length - 1 );
kstackS = stackS.Substring( 0, 1 );
posI = tabletokenS.IndexOf( kstackS, 0 );
if ( posI < 0 ) {
Console.WriteLine( kstackS + " not found in tabletokenS " +
tabletokenS );
return( "error" );
}
prioritystackI = int.Parse( tablestackS.Substring( posI, 1 ) );
} while ( priorityinputI <= prioritystackI );
stackS = kexpressionS + stackS;
}
} while ( expressionI < ( expressionS.Length - 1 ) );
I = 0 - 1;
do {
I = I + 1;
kstackS = stackS.Substring( I, 1 );
if ( ( kstackS != "#" ) && ( kstackS != "(" ) && ( kstackS !
= ")" ) ) {
resultS = resultS + kstackS;
}
} while ( I < ( stackS.Length - 1 ) );
return( resultS );
}
}
//
class CLASSStringConvertInfixToSuffixMain {
public static void Main() {
string infixS = "((2*3)^6+(4*5)+(6*7))^7";
do {
CLASSStringConvertInfixToSuffix OBJECTrpn = new
CLASSStringConvertInfixToSuffix( infixS );
Console.WriteLine( "infix = " + infixS );
Console.WriteLine( "suffix = " +
OBJECTrpn.FNStringConvertInfixToPrefixS() );
Console.Write("Type in a new infix string (type Q to quit), for
example (3+4)*5+6-7 ");
infixS = Console.ReadLine();
if ( infixS == "" ) {
infixS = "(3+4)*5+6-7";
}
} while ( infixS.ToLower() != "q" );
}
}
}
--- cut here ---------------------------------------------------------
3. -Run this code
That should show:
((2*3)^6+(4*5)+(6*7))^7
resultS is 23*6^45*+67*+7^
which is respectively the infix and suffix representation.
4. -Change expressionS to your own infix string
e.g.
expressionS = "(3+4)*5+6-7"
and recompile for another example,
e.g. that should show 34+5*6+7-
---
Note:
In order to keep it very simple and short in this
implementation:
1. Please take spaces away.
so "(3+4)*5+6-7" is OK,
but "( 3 + 4 ) * 5 + 6 - 7" is not.
2. only single characters (like a, b, c, ..., 3, 4, 5, ...)
so "a+b*c-d^f" is OK,
but "alpha*beta+gamma" is not.
3. the priorities should here be single numbers between 0 and 9
(like 0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
in your tables.
4. This program is a direct translation of the Dijkstra double
priority algorithm (see below for the link and further
description)
---
---
Note:
Compiled successfully as a console application in:
- Microsoft Visual C# command line compiler csc.exe
- Microsoft Visual Studio C#.NET
---
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Internet: see also:
---
Algorithm: Expression: Infix: Convert: Postfix: Overview: How convert
infix to postfix expression?
http://www.faqts.com/knowledge_base/view.phtml/aid/26071/fid/585
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