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; }; }