C++的逆波兰表达式的求解

#include <iostream>
#include <string>
#include <iterator>
#include "ChainStack.cpp"
using namespace std;
string reverseConvert(const string& inputString);//将中序表达式转换成逆波兰表达式
int calculateString(const string& inputString);//将逆波兰表达式求解
bool isNumber(const char e);//判断字符是否为数字
bool isSymbol(const char e);//判断字符是否为符号
bool checkLevel(const char c1, const char c2);//c1的运算级别小于c2；返回true;
int levelSymbol(const char c1);//返回符号的级别
 


int main()
{
	string Input = "2*(1+2/2) ";
	string Output = reverseConvert(Input);
	cout << Input << endl;
	cout << Output << endl;
	cout << "2*(1+2/2 = " << calculateString(Output) << endl;
	
	return 0;
}

int calculateString(const string& inputString)
{		
	ChainStack<char> resultStack;
	string temp = inputString;
	string::iterator i = temp.begin();
	for (; i !=temp.end(); ++i)
	{
		if (isNumber(*i))
		{
			resultStack.Push(*i);
		}
		else
		{
			char t1, t2;
			int result;
			resultStack.Pop(t1);
			resultStack.Pop(t2);
			if (*i=='+')
			{
				result = (t2 - '0') + (t1 - '0');
				resultStack.Push(result+'0');
			}
			if (*i == '-')
			{
				result = (t2 - '0') - (t1 - '0');
				resultStack.Push(result + '0');
			}
			if (*i == '*')
			{
				result = (t2 - '0') * (t1 - '0');
				resultStack.Push(result + '0');
			}
			if (*i == '/')
			{
				result = (t2 - '0') / (t1 - '0');
				resultStack.Push(result + '0');
			}
			if (*i == '%')
			{
				result = (t2 - '0') % (t1 - '0');
				resultStack.Push(result + '0');
			}
		}
	}
	char topChar;
	resultStack.GetTop(topChar);
	return topChar-'0';
}
bool isNumber(const char e)
{
	bool temp = false;
	switch (e)
	{
	case '0':
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
	case '9':
		temp = true;
		break;
	default:
		break;
	}
	return temp;
}
bool isSymbol(const char e)
{
	bool temp = false;
	switch (e)
	{
	case '+':
	case '-':
	case '*':
	case '/':
	case '(':
	case ')':
	case '%':
		temp = true;
		break;
	default:
		break;
	}
	return temp;
}
int levelSymbol(const char c1)
{
	int i = 0;
	if (c1 == '+' || c1 == '-')
	{
		i = 1;
	}
	if (c1 == '*' || c1 == '/' || c1 == '%')
	{
		i = 2;
	}
	return i;
}
bool checkLevel(const char c1, const char c2)
{
	return levelSymbol(c1) <= levelSymbol(c2);
}


string reverseConvert(const string& inputString)
{
	ChainStack<char> tempStack;
	string temp, returnString;
	char topChar;
	
	temp = inputString;
	string::iterator i = temp.begin();
	for (; i != temp.end(); ++i)//从左至右扫描中缀表达式
	{
		tempStack.GetTop(topChar);
		if (isNumber(*i))
		{
			returnString += *i;
		}
		else
		{
			if (isSymbol(*i))//若读取的是运算符
			{
				if (*i == '(')//该运算符为左括号"("，则直接存入运算符堆栈。
				{
					tempStack.Push(*i);
				}
				else{
						if (*i == ')')//该运算符为右括号")"，则输出运算符堆栈中的运算符到操作数堆栈，直到遇到左括号为止。
							{
								while (topChar != '(')
									{
										tempStack.Pop(topChar);
										returnString += topChar;
										tempStack.GetTop(topChar);//运算完后重新获取栈顶元素
									}
								tempStack.Pop(topChar);//把topChar='（'弹出栈
							}
						else
							{
								tempStack.GetTop(topChar);
								if (topChar == '(' || tempStack.Empty())//若运算符堆栈栈顶的运算符为左括号或者为空栈，则直接存入运算符堆栈。
										{
											tempStack.Push(*i);
										}
										//若比运算符堆栈栈顶的运算符优先级低，则输出栈顶运算符到操作数堆栈，并将当前运算符压入运算符堆栈
								else{
											while (checkLevel(*i, topChar))//如果当前符合*i比栈顶符号topChar的运算级低或者相等
											{
												tempStack.Pop(topChar);//将栈顶元素弹出赋给输出串，直到栈顶符合的运算级小于等于当前符号
												returnString += topChar;
												if(!tempStack.GetTop(topChar)) break;//如果栈为空跳出循环
												//tempStack.Push(*i);
											}
											tempStack.Push(*i);//把当前符号压入栈中
									}
							}
					}
			}
		}
	}
	while (!tempStack.Empty())
	{
		tempStack.Pop(topChar);
		returnString += topChar;
	}

	return returnString;
}