逆波兰计算器

#include
#include
#include 
#include
using namespace std;

int level(char ch);
int main()
{
	stack <char> s1, s2, s3, s4; //
	char str[10];
	int p1, p2;
	cin>>str;
	char ch;
	for(int i = 0;str[i]!='\0';i++)
	{

		 if(str[i] >='0' && str[i]<='9')
		 {
			s1.push(str[i]);
		 }
		if(str[i] == '(')
		{
			s2.push(str[i]);//左括号放入运算符堆栈
		}
		else if(str[i]== ')')
		{

			while(s2.top() != '(')
			{
				ch = s2.top();
				s2.pop();
				s1.push(ch);
			}
			s2.pop();
		}
		else if(str[i] == '+' || str[i] == '-' || str[i] == '*' || str[i] == '/')
		{
			 if(s2.empty())
			{
				s2.push(str[i]);
			}
			else if(!s2.empty() && s2.top() == '(' || s2.top() == ')')
			{
				s2.push(str[i]);
			}
			else if(!s2.empty() && level(str[i]) > level(s2.top()))
			{
				s2.push(str[i]);
			}
			else if(!s2.empty() && level(str[i]) <= level(s2.top()))
			{
				ch = s2.top();
				s2.pop();
				s1.push(ch);
				s2.push(str[i]);
			}	
		}
	}
	while(!s2.empty())
	{
		ch = s2.top();
		s2.pop();
		s1.push(ch);
	}//s1 从左到又数逆波兰
	cout<<endl;
	cout<<"逆波兰从右往左看"<<endl;
	while(!s1.empty())
	{
		ch = s1.top();
		cout<<ch<<' ';
		s3.push(ch);
		s1.pop();
	}
	cout<<endl;
	/*while(!s3.empty())
	{
		cout<
	while(!s3.empty())
	{
		if(s3.top() >= '0' && s3.top() <= '9')
		{
			s4.push(s3.top());
			s3.pop();
		}
		else if(s3.top() == '+' || s3.top() == '-' || s3.top() == '*' || s3.top() == '/')
		{
			if(s3.top() == '+')
			{s3.pop();
				p1 = s4.top() - '0';
				s4.pop();
				p2 = s4.top() - '0';
				s4.pop();
				if(s3.empty())
				{
					cout<<p1+p2<<endl;
				}
				else
				{
					s4.push(char(p1+p2+48));
				}
			}
			else if(s3.top() == '-')
			{s3.pop();
				p1 = s4.top() - '0';
				s4.pop();
				p2 = s4.top() - '0';
				s4.pop();
				if(s3.empty())
				{
					cout<<p2-p1<<endl;
				}
				else
				{
					s4.push(char(p2-p1+48));
				}
			}
			else if(s3.top() == '*')
			{s3.pop();
				p1 = s4.top() - '0';
				s4.pop();
				p2 = s4.top() - '0';
				s4.pop();
				if(s3.empty())
				{
					cout<<p1*p2<<endl;
				}
				else
				{
					s4.push(char(p1*p2+48));
				}
			}
			else if(s3.top() == '/')
			{
				s3.pop();
				p1 = s4.top() - '0';
				s4.pop();
				p2 = s4.top() - '0';
				s4.pop();
				if(s3.empty())
				{
					cout<<p2/p1<<endl;
				}
				else
				{
					s4.push(char(p2/p1+48));
				}
			}
			
		}
	}
	return 0;
}

 int level(char ch)     //优先级判断 
 {   
	  if(ch=='(')   
	  return   0;   
	  if(ch=='+'||ch=='-') 
	  return   1;   
	  if (ch=='*'||ch=='/')  
	  return   2;   
 }