30 lines
741 B
C++
30 lines
741 B
C++
|
#include <bits/stdc++.h>
|
||
|
|
|
||
|
|
using namespace std;
|
||
|
|
bool isOp(string c){
|
||
|
|
return c == "+" || c == "-" || c == "*" || c == "/";
|
||
|
|
}
|
||
|
|
int eval(string s){
|
||
|
|
stack<int> stk;
|
||
|
|
stringstream s1(s);
|
||
|
|
string c;
|
||
|
|
while (s1>>c){
|
||
|
|
if(isOp(c)){
|
||
|
|
int a = stk.top();
|
||
|
|
stk.pop();
|
||
|
|
int b = stk.top();
|
||
|
|
stk.pop();
|
||
|
|
if (c == "+") stk.push(b + a);
|
||
|
|
if (c == "-") stk.push(b - a);
|
||
|
|
if (c == "*") stk.push(b * a);
|
||
|
|
if (c == "/") stk.push(b / a);
|
||
|
|
}else
|
||
|
|
stk.push(stoi(c));
|
||
|
|
}
|
||
|
|
return stk.top();
|
||
|
|
}
|
||
|
|
int main() {
|
||
|
|
string s = "24 9 6 3 / + 5 - * 4 +";
|
||
|
|
cout << "answer:" << eval(s) << endl;
|
||
|
|
return 0;
|
||
|
|
}
|