hdu 1237 简单计算器有感

话说在数据结构上看完之后就来敲了这题，敲完提交后wa于是找错，发现没考虑0 + 1这种数据，直接跳出了，于是改了后来还是wa,于是我又查，发现1 - 2 + 4输出的是-5违反了操作符优先级相同从左往右运算的原则，后来发现1 / 2 / 3 * 2 * 3这组也错了，于是看了书，发现是书上的优先级表错了于是改之就过了，这个代码稍作修改就能适用于带括号的运算
同时给几组比较容易错的吧
0 + 1
1.00
1
1.00
1 - 2 + 4
3.00
1 * 2 + 1 + 1 * 2 * 3 / 3 - 1 + 2 / 1
6.00
1 / 2 / 3 * 2 * 3
1.00
下面是代码，希望帮到你们

#include<iostream>
#include<stack>
#include<cctype>
#include<string>
#include<map>
using namespace std;
const int Max=220;
char You[8][8]={
{' ',' ',' ',' ',' ',' ',' ',' '}
,{' ','<','<','<','<','<','>','>'}
,{' ','<','<','<','<','<','>','>'}
,{' ','>','>','<','<','<','>','>'}
,{' ','>','>','<','<','<','>','>'}
,{' ','<','<','<','<','<','=',' '}
,{' ','>','>','>','>',' ','>','>'}
,{' ','<','<','<','<','<',' ','='}};
double opera(double a,double b,char op)
{
switch(op)
{
case '-':return a-b;
case '+':return a+b;
case '*':return a*b;
case '/':return a/b;
}
return 0;
}
double Oper(string chuchun[Max],int len)
{
map<char,int> Map;
Map['+']=1;
Map['-']=2;
Map['*']=3;
Map['/']=4;
Map['(']=5;
Map[')']=6;
Map['#']=7;
stack<char> optr;
stack<double > optd;
int i,j;
optr.push('#');
for(i=0;i<len;i++)
{
if(isdigit(chuchun[i][0]))
{
int temp=1;
int sum=0;
for(j=chuchun[i].size()-1;j>=0;j--)
{
sum+=(chuchun[i][j]-'0')*temp;
temp*=10;
}
optd.push(sum);
}
else
{
bool on_off=true;
while(on_off)
{
char op=optr.top();
if(optr.size()==0)
break;
switch(You[Map[chuchun[i][0]]][Map[op]])
{
case '<':
{
optr.pop();
double a=optd.top();
optd.pop();
double b=optd.top();
optd.pop();
double res=opera(b,a,op);
optd.push(res);
}break;
case '=':
{
optr.pop();
on_off=false;
}break;
case ' ':
case '>':
{
optr.push(chuchun[i][0]);
on_off=false;
}break;
}
}
}
}
return optd.top();
}
int  saveword(string str[Max],string & Now)
{
int len=0;
while(Now.find(" ")!=string::npos)
{
int now=Now.find(" ");
str[len++]=Now.substr(0,now);
Now.erase(0,now);
while(Now[0]==' ')
Now.erase(Now.begin());
}
if(Now.size()!=0)
str[len++]=Now;
return len;
}
int main()
{
string str;
string chuchun[Max];
while(getline(cin,str))
{
if(str.size()==1&&str[0]=='0')
break;
int Len=str.size();
int len;
len=saveword(chuchun,str);
chuchun[len++]="#";
double ch=Oper(chuchun,len);
printf("%.2lf/n",ch);
}
return 0;
}