每日一题4.19.2

每日一题4.19.2

Emacs计算器

代码实现：

#include<iostream>
#include<vector>
#include<string>
#include<stack>
using namespace std;
int main()
{
	int n;
	int a, b, ret;
	while (cin >> n)
	{
		if (n == 0)
			continue;
		vector<string> s(n);
		stack<int> m;
		for (int i = 0; i < n; i++)		
		{
			cin >> s[i];
		}
		for (int i = 0; i < n; i++)
		{
			if (s[i][0] >= '0'&&s[i][0] <= '9')
				m.push(atoi(s[i].data()));	
			else
			{
				a = m.top();
				m.pop();
				b = m.top();
				m.pop();
				switch (s[i][0])
				{
				case '+': m.push(a + b);
					break;
				case '-': m.push(b - a);
					break;
				case '*': m.push(a * b);
					break;
				case '/': m.push(b / a);
					break;
				}
			}
		}
		cout << m.top() << endl;
	}
	return 0;
}