Get value using Regular Expression

標題：C/C++使用正規表示法取值
VC++ (main.cpp)：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52

#include "stdafx.h" #include <iostream> #include <regex> //string lib here using namespace std; int _tmain(int argc, _TCHAR* argv[]) { cout << "--- Example 1 ---" << endl; //String Match string strA = "13393774"; smatch matchA; regex regA("[0-9]+"); if(regex_match(strA, matchA, regA)) { cout << atof(matchA[0].str().c_str()) << " is number." << endl; } else { cout << "Not a number." << endl; } cout << "--- Example 2 ---" << endl; //String Match string strB = "-4.472136e-001"; smatch matchB; regex regB("[+-]?(?=\.[0-9]|[0-9])(?:[0-9]+)?(?:\.?[0-9]*)(?:[eE][+-]?[0-9]+)?"); if(regex_match(strB, matchB, regB)) { cout << atof(matchB[0].str().c_str()) << " is number." << endl; } else { cout << "Not a number." << endl; } cout << "\n--- Example 3 ---" << endl; //String Search string strC = " facet normal 0.000000e+000 -4.472136e-001 8.944272e-001"; smatch matchC; regex regC(" *facet normal \ ([+-]?(?=\.[0-9]|[0-9])(?:[0-9]+)?(?:\.?[0-9]*)(?:[eE][+-]?[0-9]+)?) \ ([+-]?(?=\.[0-9]|[0-9])(?:[0-9]+)?(?:\.?[0-9]*)(?:[eE][+-]?[0-9]+)?) \ ([+-]?(?=\.[0-9]|[0-9])(?:[0-9]+)?(?:\.?[0-9]*)(?:[eE][+-]?[0-9]+)?)"); if(regex_match(strC, matchC, regC)) { cout << "Facet normal: ("; cout << atof(matchC[1].str().c_str()) << ", "; cout << atof(matchC[2].str().c_str()) << ", "; cout << atof(matchC[3].str().c_str()) << ")" << endl; } else { cout << "Not Match." << endl; } return 0; }

說明：
在C/C++中使用正規表示式取得數值。