四则运算算法，欢迎拍砖

看Mark Aliens的Data Structure and Algorithm Analysis时，发现一个不错的四则运算算法，下面做下了下简单的实现。

代码实现如下，欢迎大家拍砖。

 

/********************************************************************created:2009/10/09created:9:10:2009 18:43filename: BaseOperate.cppfile path:c:/Jackafx_App/BaseOperatorfile base:BaseOperatefile ext:cppauthor:jackafxpurpose:arithmetic algorithm*********************************************************************/#include <iostream>#include <string>#include <stack>#include <queue>#include <math.h>#include <stdlib.h>using namespace std;#ifndefUINTtypedef unsigned int UINT;#endifstack<string> Stack;stack<double> Output;queue<string> Queue;char OpList[] ={'+', '-', '*', '/', '(', ')'};double Calculate( const char op, bool& bSuccess ){double a, b;double fResult = 0;bSuccess = false;b = Output.top();Output.pop();a = Output.top();Output.pop();switch ( op ){case '+':fResult = a + b;bSuccess = true;break;case '-':fResult = a - b;bSuccess = true;break;case '*':fResult = a * b;bSuccess = true;break;case '/':fResult = a / b;bSuccess = true;break;default:break;}return fResult;}double Calculate( string op, bool& bSuccess ){char chop = op[0];return Calculate( chop, bSuccess );}UINT GetPriority( string op ){string str_op = op;UINT uiPriority = 0;if ( str_op == "+" || str_op == "-" ){uiPriority = 1;}else if ( str_op == "*" ||str_op == "/"){uiPriority = 2;}else;// do nothingreturn uiPriority;}bool Operate( string op ){string str_in = op;double dReuslt = 0;bool bsuccess = false;UINT uiPriority = GetPriority( str_in );if ( uiPriority == 0 ){if ( str_in == "(" ){Stack.push( str_in );}else if ( str_in == ")" ){while ( Stack.top() != "(" ){dReuslt = Calculate( Stack.top(), bsuccess );if ( bsuccess ){Output.push( dReuslt );Stack.pop();}else return false;}Stack.pop();// pop the "("}else{dReuslt = atof( str_in.c_str() );Output.push( dReuslt );// it's a number, just do it.}return true;}// normal operator// and we need do something herewhile ( !Stack.empty() && GetPriority( Stack.top() ) >= uiPriority ){dReuslt = Calculate( Stack.top(), bsuccess );if ( bsuccess ){Output.push( dReuslt );Stack.pop();}else return false;}Stack.push( str_in );// finally, push the operatorreturn true;}bool IsOperator( const char op ){int nIndex = 0;while ( nIndex < 6 ){if ( OpList[nIndex] == op )return true;nIndex++;}return false;}bool PutStrToQueue( char* str ){char* pOp = str;string str_put_in;string tmp;while ( *pOp != '/0' ){tmp = *pOp;if ( IsOperator( *pOp ) ){if ( !Queue.empty() && !str_put_in.empty() ){Queue.push( str_put_in );// it's ok}// check weather it is empty, if not, clear it.if ( !str_put_in.empty() )str_put_in.clear();Queue.push( tmp );}else{str_put_in.append( tmp );// put the characters together}pOp++;}pOp--;if ( *pOp != ')'){Queue.push( str_put_in );}return true;}int main( ){string test;PutStrToQueue( "((10+5)*(9-6)-13*14)*2" );while ( !Queue.empty() ){test = Queue.front();if ( !Operate( test ) )return -1;Queue.pop();}// then, do the rest of workwhile( !Stack.empty() ){test = Stack.top();if ( !Operate( test ) )return -1;Stack.pop();}return 0;}