基于堆栈的计算器代码

#include<iostream>#include<cstdio>#include<cstring> #include<string>#include<stack>#include<cmath>using namespace std;stack<double>b;   //操作数栈 stack<int>c;   //操作符栈 int main(){       puts("**********************************************************************");       puts("*                                                                    *");       puts("*                  简     易     计     算      器                   *");       puts("*                                                                    *");       puts("*                       软件2班      王凯旋                          *");       puts("**********************************************************************\n\n");       string a;long l,i,j;double sum,t,sum1;       double deal(int);       recycle://循环起点        while(getline(cin,a))       {l=a.size();//得到算式        if(l==0)//特殊情况处理         {printf("您没有输入数据\n请输入数据:\n\n");continue;}        while(!b.empty()) b.pop();while(!c.empty()) c.pop();//清空栈        a[l]='#';i=0;c.push(1);//栈初始化    int neg=0;       while(1)                    {            if((a[i]>='0'&&a[i]<='9')&&i<l)//得到数据             {            sum=0;            while((a[i]>='0'&&a[i]<='9')&&i<l)            {sum=sum*10+a[i]-'0'; i++;}            sum1=0;            if(a[i]=='.')            {                  i++;t=0.1;                  while((a[i]>='0'&&a[i]<='9')&&i<l)                  {sum1=sum1+(a[i]-'0')*t;t=t*0.1;i++;}                         }if(neg)            {                   if(sum+sum1==0)                       b.push(0);                   else                       b.push((-1.0)*(sum+sum1));                   neg=0;            }else b.push(sum+sum1);            }            switch(a[i])//操作符处理             {                case '#':{while((c.top())!=1)                         {b.push(deal(c.top()));c.pop();}                         if(b.top()==0) printf("=0\n\n");                          else printf("=%g\n\n",b.top());                          b.pop();                          goto recycle;}               case '+':{if(c.top()<3)c.push(3);                        else{                             while(c.top()>=3)                             {b.push(deal(c.top()));c.pop();}                             c.push(3);}                        }break;               case '-':{if(i==0||a[i-1]=='(') neg=1;else if(c.top()<3)c.push(4);else{                             while(c.top()>=3)                             {b.push(deal(c.top()));c.pop();}                             c.push(4);}                                            }break;               case '*':{if(c.top()<5)c.push(5);                         else                         {                             while(c.top()>=5)                             {b.push(deal(c.top()));c.pop();}                             c.push(5);}                        }break;               case '/':{if(c.top()<5)c.push(6);                         else                         {                             while(c.top()>=5)                             {b.push(deal(c.top()));c.pop();}                             c.push(6);}                        }break;               case '(':c.push(2);break;                                    right:               case ')':{while(c.top()!=2)                                               {                               if(c.top()==4)                               {                                      j=i-1;                                      while(a[j]!='-')j--;                                      j--;                                      if(a[j]=='(')                                      {c.pop();b.push(b.top()*(-1));b.pop();}                                      else{b.push(deal(c.top()));c.pop();}                                                }                               else{b.push(deal(c.top()));c.pop();}                                            }                        c.pop();                        }break;               case '^':{if(c.top()<7)c.push(7);                        else                        {                             while(c.top()>=7)                             {b.push(deal(c.top()));c.pop();}                             c.push(7);                        }}break;            }i++;}} }double deal(int n)//计算处理 {     double x,y;     x=b.top();b.pop();y=b.top();b.pop();     switch(n)     {          case 3:return(x+y);break;          case 4:return(y-x);break;          case 5:return(x*y);break;          case 6:{                      if(x==0)                      {printf("数据错误（除数不能为零）下面的结果无意义\n");return 0;}                      return(y/x);                  }break;          case 7:{                      if(x==0&&y==0)                      {printf("数据错误（0^0无意义）下面的结果无意义\n");return 0;}                      else return(pow(y,x));                  }break;     };    }