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OI-source/history_source/信息学奥赛一本通/2.4.1.cpp
2023-08-03 09:22:52 +08:00

31 lines
537 B
C++

#include<iostream>
#include<string>
#include<math.h>
using namespace std;
bool isop(string n)
{
if(n=="+") return 1;
if(n=="-") return 1;
if(n=="*") return 1;
if(n=="/") return 1;
return 0;
}
double operation()
{
string sr;
cin>>sr;
if(!isop(sr)) return atof(sr.c_str());
switch(sr[0])
{
case '+': return operation()+operation();
case '-': return operation()-operation();
case '*': return operation()*operation();
case '/': return operation()/operation();
}
}
int main()
{
printf("%.6lf\n",operation());
return 0;
}