c++，中缀表达式转为后缀表达式

int in_stack_priority(char c)
{
	int ret;
	switch (c)
	{
	case '+':
	case '-': ret = 2;break;
	case '*':
	case '/': ret = 4; break;
	case '(': ret = 0; break;
	}
	return ret;
}

int out_stack_priority(char c)
{
	int ret;
	switch (c)
	{
	case '+':
	case '-': ret = 1;break;
	case '*':
	case '/': ret = 3; break;
	case '(': ret = 5; break;
	case ')': ret = 0; break;
	}
	return ret;
}



vector infix_to_postfix(vector& infix)
{
	vector postfix;
	stack ostack;
	string temp;
	for (const auto& x : infix)
	{
		if (isdigit(x[0]))
		{
			postfix.push_back(x);
		}
		else
		{
			while (!ostack.empty() && in_stack_priority(ostack.top()[0]) > out_stack_priority(x[0]))
			{
				temp = ostack.top(), ostack.pop();
				postfix.push_back(temp);
			}
			if (ostack.empty() || in_stack_priority(ostack.top()[0]) < out_stack_priority(x[0]))
			{
				ostack.push(x);
			}
			else
			{
				ostack.pop();
			}
		}
	}
	while (!ostack.empty())
	{
		temp = ostack.top(), ostack.pop();
		postfix.push_back(temp);
	}
	return postfix;
}

int main()
{
	vector infix = { "(", "3", "+", "1", ")", "*", "(", "4", "*", "3", ")" };
	vector postfix = infix_to_postfix(infix);
	for (const auto& x : postfix)
	{
		cout << x << " " << endl;
	}
}