简单计算器

类型一：

输入：当一行中只有0时输入结束

输出：对每个测试用例输出一行，精确到小数点后两位

备注：这个题的细节是可以输入浮点数，书上的代码是只能输入整型数字

#include <stdio.h>
#include <iostream>
#include <stack>
#include <queue>
#include <map>
#include <string>
using namespace std;

struct node
{
    double num;
    char op;
    bool flag;
}Node;

stack<node> s;
queue<node> q;
string str;
map<char, int> op;

void Change()
{
    node temp;
    for(int i = 0; i < str.length();)
    {
        if(str[i] >= '0' && str[i] <= '9')
        {
            temp.flag = true;
            temp.num = str[i++] - '0';
            if(str[i] == '.')
            {
                i++;
                double product = 0.1;  //这里写错
                while(i < str.length() && str[i] >= '0' && str[i] <= '9')
                {
                    temp.num = temp.num + (str[i] - '0') * product;
                    product = product * 0.1;
                    i++;//这一句漏了
                }
            }
            while(i < str.length() && str[i] >= '0' && str[i] <= '9')
            {
                temp.num = temp.num * 10 + (str[i] - '0');
                i++;
            }
            q.push(temp);
        }
        else
        {
            temp.flag = false;
            while(!s.empty() && op[s.top().op] >= op[str[i]])
            {
                q.push(s.top());
                s.pop();
            }
            temp.op = str[i];
            s.push(temp);
            i++;//这一句漏了
        }
    }
    while(!s.empty())
    {
        q.push(s.top());
        s.pop();
    }
}

double Cal()
{
    double temp1, temp2;
    node cur, temp;
    while(!q.empty())
    {
        cur = q.front();
        q.pop();//这句漏了
        if(cur.flag == true) //这里写成1了
        {
            s.push(cur);
        }
        else
        {
            temp2 = s.top().num;
            s.pop();
            temp1 = s.top().num;
            s.pop();
            temp.flag = true;//漏了
            if(cur.op == '+')
            {
                temp.num = temp1 + temp2;
            }
            else if(cur.op == '-')
            {
                temp.num = temp1 - temp2;
            }
            else if(cur.op == '*')
            {
                temp.num = temp1 * temp2;
            }
            else
                temp.num = temp1 / temp2;
			s.push(temp);
        }
    }
    return s.top().num;
}

int main(void)
{
    op['+'] = op['-'] = 1;
    op['*'] = op['/'] = 2;
    while(getline(cin, str), str != "0")
    {
        for(string::iterator it = str.begin(); it != str.end(); it++)//这里写成it--了
        {
            if(*it == ' ')
            {
                str.erase(it);
            }
        }
        while(!s.empty())
        {
            s.pop();
        }
        Change();
        printf("%.2f\n", Cal());
    }
    return 0;
}