C++ 栈 用于括号匹配问题（详细版+题目）

code:

#include<iostream>
#include<stack>
#include<string>
using namespace std;
int main()
{
	string s;
	stack<int> mystack;
	while(cin>>s)
	{
		string news = s;

		int len = s.length();

		for(int i=0;i<len;i++)
		{
			//判断输入的字符，进行相应的处理
			if(s[i] == '(')
			{
				mystack.push(i);
				news[i] = ' ';
			}
			else if(s[i] == ')')
			{
				if(mystack.empty() == true)
					news[i] = '?';
				else
				{
					mystack.pop();
					news[i] = ' ';
				}
			}
			else
				news[i] = ' ';
		}
		//剩下的（ 无法匹配，进行处理
		while(!mystack.empty())
		{
			news[mystack.top()] = '$';
			mystack.pop();
		}
		cout<<s<<endl<<news<<endl;
	}

	return 0;
}