1 #include <iostream>
2 #include <cstdio>
3 #include <cstring>
4 #include<stack>
5 #include<vector>
6 using namespace std;
7 int main()
8 {
9 char str[210];
10 while (1) {
11 stack<double>a;stack<char>b;
12 gets_s(str);
13 int len = strlen(str);
14 if (str[0] == '0'&&len==1)break;
15 for (int i = 0;i < len;i++) {
16 if (str[i] == ' ')continue;
17 else if (str[i] != '+' && str[i] != '-' && str[i] != '*' && str[i] != '/') {
18 double res = 0;
19 while (str[i] != ' '&&i<len) {
20 res = res * 10 + str[i] - '0';i++;
21 }
22 a.push(res);
23 }
24 else if (str[i] == '*' || str[i] == '/') {
25 int pos = i;
26 i+=2;
27 double res = 0;
28 while (str[i] != ' ' && i < len) {
29 res = res * 10 + str[i] - '0';i++;
30 }
31 double ans = 0;
32 if (str[pos] == '*')ans = a.top() * res;
33 else if (str[pos] == '/')ans = a.top() / res;
34 a.pop();
35 a.push(ans);
36 }
37 else if (str[i] == '+' || str[i] == '-')b.push(str[i]);
38 }
39 vector<double>A;vector<char>B;
40 while (!a.empty())A.push_back(a.top()), a.pop();
41 while (!b.empty())B.push_back(b.top()), b.pop();
42 reverse(A.begin(), A.end());reverse(B.begin(), B.end());
43 double num = A[0];
44 for (int i = 1, j = 0;i<A.size(),j<B.size();j++,i++) {
45 if (B[j] == '+')num += A[i];
46 else num -= A[i];
47 }
48 printf("%.2f\n", num);
49 }
50 }
51 //先将优先级高的乘除运算掉
52 //4 + 2 * 5 - 7 / 11 变为 4+10-0.63
