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中缀表达式转化为后缀表达式

//Copyright by abilitytao

//All right not reserved!!

 

 

#include 
<process.h>

#include 
<iostream.h>

#include 
<conio.h>

#include 
<stdlib.h>

#include 
<math.h>

#include 
<stack>

#include 
<cstring>

#include 
<ctype.h>

using namespace std;

 

struct formula

{

       
char numormark[100];

}
;

 

/**////////////////////////////////////////////////////////////

/////////////////////定义problem类/////////////////////////

///////////////////////////////////////////////////////////


 

class Aeasyproblem

{

private:

       
int formulalen;

       
char temp[1000];

       formula 
in[1000];

       formula pos[
1000];

public:

       
void inputtheformula();

       
void intoin();//用于将中缀表达式放入结构体数组,从而实现数字与运算符的分离;

       
void intopos();//用于将中缀表达式转化成后缀表达式;

       
void showthepos();

}
;

 

void Aeasyproblem::inputtheformula()

{

       cin
>>temp;

}


void Aeasyproblem::intoin()//这是用于解析输入的字符串的函数,将算式中的每个个体存入自己声明的结构体中;

{

       formulalen
=0;

       
int templen;

       
int temlen;

       
char tem[100];

 

      

       templen
=strlen(temp);

       
int i;

       
int j;

       j
=0;

       
for(i=0;i<templen;i+=temlen)

       
{

              
if(isdigit(temp[i]))

              
{

                     sscanf(
&temp[i],"%[^-^+^*^/^(^)]",tem);

                     temlen
=strlen(tem);

                     strcpy(
in[j].numormark,tem);

                     formulalen
++;

                     j
++;

              }


              
else

              
{

                     temlen
=1;

                     
in[j].numormark[0]=temp[i];

                     
in[j].numormark[1]='\0';

                     formulalen
++;

                     j
++;

              }


       }


}


 

 

 

 

void Aeasyproblem::intopos()//这是用于将中缀表达式转化成后缀表达式的函数

{

       
/**//////////////////'(' ')''+''-''*''/''='

       
static int isp[7]=0,19,12,12,13,13,0};

       
static int icp[7]={20,19,12,12,13,13,0};

       
int precedence_sta;

       
int precedence_token;

 

       stack
<formula>sta;

       
int i;

       
int j;

       
char token[100];

       formula start;

       strcpy(start.numormark,
"\0");

       sta.push(start);

       j
=0;

       
for(i=0;i<formulalen;i++)

       
{

             

              strcpy(token,
in[i].numormark);

              
if(strcmp(token,"\0")==0)

                     
break;

              
if(isdigit(token[0]))

              
{

                     strcpy(pos[j].numormark,token);

                     j
++;

              }


              
else if(strcmp(token,")")==0)

              
{

                     
while(strcmp(sta.top().numormark ,"(")!=0)

                     
{

                            strcpy(pos[j].numormark,sta.top().numormark);

                            j
++;

                            sta.pop();

                     }


                     sta.pop();

              }


              
else

              
{

                            
if(strcmp(sta.top().numormark,"(")==0)

                                   precedence_sta
=0;

                            
if(strcmp(sta.top().numormark,")")==0)

                                   precedence_sta
=19;

                            
if(strcmp(sta.top().numormark,"+")==0)

                                   precedence_sta
=12;

                            
if(strcmp(sta.top().numormark,"-")==0)

                                   precedence_sta
=12;

                            
if(strcmp(sta.top().numormark,"*")==0)

                                   precedence_sta
=13;

                            
if(strcmp(sta.top().numormark,"/")==0)

                                   precedence_sta
=13;

                            
if(strcmp(sta.top().numormark,"\0")==0)

                                   precedence_sta
=0;

                            
if(strcmp(token,"(")==0)

                                   precedence_token
=20;

                            
if(strcmp(token,")")==0)

                                   precedence_token
=19;

                            
if(strcmp(token,"+")==0)

                                   precedence_token
=12;

                            
if(strcmp(token,"-")==0)

                                   precedence_token
=12;

                            
if(strcmp(token,"*")==0)

                                   precedence_token
=13;

                            
if(strcmp(token,"/")==0)

                                   precedence_token
=13;

                            
if(strcmp(token,"\0")==0)

                                   precedence_token
=0;

                     
while(precedence_sta>=precedence_token)

                     
{

                                   pos[j]
=sta.top();

                                   j
++;

                                   sta.pop();

                            
if(strcmp(sta.top().numormark,"(")==0)

                                   precedence_sta
=0;

                            
if(strcmp(sta.top().numormark,")")==0)

                                   precedence_sta
=19;

                            
if(strcmp(sta.top().numormark,"+")==0)

                                   precedence_sta
=12;

                            
if(strcmp(sta.top().numormark,"-")==0)

                                   precedence_sta
=12;

                            
if(strcmp(sta.top().numormark,"*")==0)

                                   precedence_sta
=13;

                            
if(strcmp(sta.top().numormark,"/")==0)

                                   precedence_sta
=13;

                            
if(strcmp(sta.top().numormark,"\0")==0)

                                   precedence_sta
=0;

                            
if(strcmp(token,"(")==0)

                                   precedence_token
=20;

                            
if(strcmp(token,")")==0)

                                   precedence_token
=19;

                            
if(strcmp(token,"+")==0)

                                   precedence_token
=12;

                            
if(strcmp(token,"-")==0)

                                   precedence_token
=12;

                            
if(strcmp(token,"*")==0)

                                   precedence_token
=13;

                            
if(strcmp(token,"/")==0)

                                   precedence_token
=13;

                            
if(strcmp(token,"\0")==0)

                                   precedence_token
=0;

                     }


                     strcpy(start.numormark,token);

                    

                            sta.push(start);

              }


       }


       
while(strcpy(token,sta.top().numormark))

 

       
{

              
if(strcmp(token,"\0")==0)

                     
break;

              pos[j]
=sta.top();

              j
++;

              sta.pop();

       }


       strcpy(pos[j].numormark,
"\0");

 

}


 

void Aeasyproblem::showthepos()

{

       
int i;

       
for(i=0;strcmp(pos[i].numormark,"\0")!=0;i++)

       
{

             

              cout
<<pos[i].numormark<<' ';

 

       }


       cout
<<'\b'<<endl<<endl;

      

}


/**////////////////////////////////////////////////////////////////////////////////////////////////

////////////////////////////////Problem类定义完成/////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////////////////////////


 

 

 

int main ()

{

       Aeasyproblem justforfun;

       
while(1)

       
{

              justforfun.inputtheformula();

              justforfun.intoin();

              justforfun.intopos();

              justforfun.showthepos();

       }


       
return 0;

}

posted on 2009-07-14 16:37 abilitytao 阅读(310) 评论(0)  编辑 收藏 引用


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