hdu 3347 Calculate the expression

/*<br />這是胡大牛給我們的講座<br />Orz<br />*/<br />#include <iostream><br />#include <sstream><br />#include <map><br />#include <string><br />using namespace std;<br />map<string, int> df;<br />int main()<br />{<br />int t;<br />cin >> t;<br />while(t--)<br />{<br />int n;<br />cin >> n;<br />string a, b;<br />int c;<br />df.clear();<br />for(int i = 1; i < n; i ++)<br />{<br />cin >> a >> b >> c;<br />df[a] = c;<br />}<br />string str;<br />getchar(); // 接受斷行符號符<br />getline(cin, str);<br />stringstream ss(str); // 定義輸入資料流<br />string str1;<br />int sign = 1;<br />int sum = 0;<br />while( ss >> str1)<br />{<br />if(str1 == "-")<br />{<br />sign = -1;<br />}<br />if(str1 == "+")<br />{<br />sign = 1;<br />}<br />if(str1 == "=")<br />{<br />break;<br />}<br />if(isalpha(str1[0])) // 判斷是否是字母<br />{<br />if(df.find(str1) != df.end())<br />{<br />sum += df[str1] * sign;<br />}<br />}<br />else<br />{<br />int temp;<br />temp = atoi(str1.c_str());// 轉換成char 在轉化成int<br />sum += temp * sign;<br />}<br />}<br />cout << sum << endl;<br />}<br />}