【C++习题】18.逆波兰表达式求值

题目：逆波兰表达式求值

链接🔗：逆波兰表达式求值

题目：

代码：

class Solution {public:int evalRPN(vector<string>& tokens) {stack<int> s;for (size_t i = 0; i < tokens.size(); ++i){string& str = tokens[i];// str为数字if (!("+" == str || "-" == str || "*" == str || "/" == str)){s.push(atoi(str.c_str()));}else{// str为操作符int right = s.top();s.pop();int left = s.top();s.pop();switch (str[0]){case '+':s.push(left + right);break;case '-':s.push(left - right);break;case '*':s.push(left * right);break;case '/':// 题目说明了不存在除数为0的情况s.push(left / right);break;}}}return s.top();}
};