中序表达式转换成后序表达式，并依据后序表达式计算结果，程序出现非法操作，请高手指点
代码如下
#include <iostream>#include <stack>#include <queue>#include <string>#include <stdlib.h>using std::iostream;using std::cout;using std::cin;using std::endl;using std::stack;using std::queue;using std::string;void CenToRear(queue<char> &s1,stack<char> &s2,string str)//将前序表达式转换成后序表达式{ char cs; int index=0; while(index<str.length())//此处是否越界？ { cs=str[index]; if(cs>='0'&&cs<='9') s1.push(cs); else { s1.push(' '); if(cs=='*' || cs=='/') { if(s2.top()=='*' || s2.top()=='/') { s1.push(s2.top()); s2.pop(); } s2.push(cs); } if(cs=='+' || cs=='-') { if(s2.empty()) s2.push(cs); else { while(!s2.empty()) { s1.push(s2.top()); s2.pop(); } s2.push(cs); } } } index++; } while(!s2.empty()) { s1.push(s2.top()); s2.pop(); }}int main(){ string str; queue<char> q; stack<char> s; char ch; int value=0; int index=0; int ldata=0; stack<int> sdata; cout<<"Please enter your expression:\n"; while(cin>>str) { CenToRear(q,s,str); while(!q.empty()) { if(q.front()>='0'&&q.front()<='9') { value*=10; value+=atoi(&q.front()); } else { if(q.front()==' ') { sdata.push(value); value=0; } if(q.front()=='*' || q.front()=='/' || q.front()=='+' || q.front()=='-') { ch=q.front(); switch(ch)//对不同运算符进行相应处理 { case '+': ldata=sdata.top(); sdata.pop(); ldata+=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; case '-': ldata=sdata.top(); sdata.pop(); ldata-=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; case '*': ldata=sdata.top(); sdata.pop(); ldata*=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; case '/': ldata=sdata.top(); sdata.pop(); ldata/=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; default: break; } } } q.pop(); } cout<<"The result is:"<<sdata.top(); cout<<endl; cout<<"Please enter your expression:\n"; }}
#include <iostream>#include <stack>#include <queue>#include <string>#include <stdlib.h>using std::iostream;using std::cout;using std::cin;using std::endl;using std::stack;using std::queue;using std::string;void CenToRear(queue<char> &s1,stack<char> &s2,string str)//将前序表达式转换成后序表达式{ char cs; int index=0; while(index<str.length())//此处是否越界？ { cs=str[index]; if(cs>='0'&&cs<='9') s1.push(cs); else { s1.push(' '); if(cs=='*' || cs=='/')//有改动 { while (!s2.empty() && (s2.top()=='*' || s2.top()=='/')) { s1.push(s2.top()); s2.pop(); } s2.push(cs); } if(cs=='+' || cs=='-')//有改动 { while (!s2.empty()) { s1.push(s2.top()); s2.pop(); } s2.push(cs); } } index++; } s1.push(' '); //有改动 while(!s2.empty()) { s1.push(s2.top()); s2.pop(); }}int main(){ string str; queue<char> q; stack<char> s; char ch; int value=0; int index=0; int ldata=0; stack<int> sdata; cout<<"Please enter your expression:\n"; while(cin>>str) { CenToRear(q,s,str);#if 0 while (!q.empty()) { cout << q.front(); q.pop(); } system("pause");#endif while(!q.empty()) { if(q.front()>='0'&&q.front()<='9') { value*=10; value+=q.front()-'0'; } else { if(q.front()==' ') { sdata.push(value); value=0; } if(q.front()=='*' || q.front()=='/' || q.front()=='+' || q.front()=='-') { ch=q.front(); switch(ch)//对不同运算符进行相应处理 { case '+': ldata=sdata.top(); sdata.pop(); ldata+=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; case '-': ldata=sdata.top(); sdata.pop(); ldata-=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; case '*': ldata=sdata.top(); sdata.pop(); ldata*=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; case '/': ldata=sdata.top(); sdata.pop(); ldata/=sdata.top(); sdata.pop(); sdata.push(ldata); ldata=0; break; default: break; } } } q.pop(); } cout<<"The result is:"<<sdata.top(); cout<<endl; cout<<"Please enter your expression:\n"; }}Please enter your expression:1+2*3+9The result is:16Please enter your expression: