讲解LeetCode第227题：基本计算器||（完整代码）

//基本计算器||——数组模拟栈
#include<iostream>
#include<vector>
#include<string>
#include<numeric>
using namespace std;

class Solution {
public:
    int calculate(string s)
    {
        vector<int>stk;
        char preSign='+';
        int num=0;
        int n=s.length();

        for(int i=0;i<n;i++)
        {
            if(isdigit(s[i]))
            {
                num=num*10+int(s[i]-'0');
            }

            if(!isdigit(s[i])&&s[i]!=' '||i==n-1)
            {
                switch(preSign)
                {
                case '+':
                  stk.push_back(num);
                  break;
                case '-':
                  stk.push_back(-num);
                  break;
                case '*':
                  stk.back()*=num;
                  break;
                default:
                  stk.back()/=num;
                }
                preSign=s[i];
                num=0;
            }
        }
        return accumulate(stk.begin(),stk.end(),0);
    }
};

int main()
{
	string s = "333*2+2-3";

	Solution value;
	int result = value.calculate(s);

	cout << "计算器的计算结果是：" << result << endl;

	return 0;
}

vector<int>stk;
char preSign='+';
int num=0;

int(s[i]-'0')

if(isdigit(s[i]))
{
   num=num*10+int(s[i]-'0');
}

stk.back()*=num;
stk.back()/=num;

#include<numeric>

return accumulate(stk.begin(),stk.end(),0);