[基础-001]C++字符串转换(char*，const char*，string)

1. string转const char*

 string str ="abc";

 const char* charArr = str.c_str();

2. const char*转string

 const char* charArr = "abc";

 string str(charArr);

3. string转char*

 string str ="abc";

 char* charArr;

 const int len = str.length();

 charArr =new char[len+];

 strcpy(charArr, str.c_str());

4. char*转string

 char* charArr ="abc";

 string str(c);

5. const char*转char*

 const char* charArr1 ="abc";

 char* charArr2 = new char[]; // 足够长

 strcpy(charArr1, charArr2)