[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)