C++ 中涉及到的 字符串轉換 std::string CString char* Int 等

1.轉換成char *
 string strSTL = "string of STL";
 CString strMFC = "string of MFC";
 int strINT = 100;

 const char * str1;
 str1 = strSTL.data();
 str1 = strSTL.c_str();

 char str2[1024] = "";
 strSTL.copy(str2 , strSTL.size() , 0);
 *(str2 + strSTL.size()) = '\0';

 str1 = strMFC;
 sprintf_s(str2 , "%d" , strINT );

2.轉換成STL
 char strC[] = "string of C style";
 CString strMFC = "string of CString";
 int strINT = 100;

 string str ;
 str = strC;
 str = strMFC;
 
 stringstream ss;
 ss << strINT;
 str = ss.str();

3.轉換成MFC
 string strSTL = "string of strSTL";
 char strC[] = "string of strC";
 int strINT = 100;

 CString str;
 str = strSTL.c_str();
 str = strC;

 str.Format("%d" , strINT);

4.轉換成Int
 string strSTL = "100";
 CString strMFC = "200";
 char strC[] = "300'";

 int i = 0;

 i = atoi(strSTL.c_str());
 i = atoi(strMFC);
 i = atoi(strC);

5.使用stringstream 可以將任意的轉換成 string
 
 stringstream ss;

ss << anything;
 ss.str(); 可以得到string
 ss.str("") 可以清除stringstream 的內容

6.將string 轉換成 數字的模版函數
 
 template <class Type>  Type stringToNum(const string& str) 
 { 
   istringstream iss(str); 
   Type num; 
   iss >> num; 
   return num;     
 }