C++ char*，const char*，string的相互转换

1.const char*转char*

    const char* c_s = "abc";

    char * c = new char(100);

    strcpy(c,c_s);

2.string 转char*

    string s = "abc";

    char * c;

    const int len = s.length();

    c = new char(len+1);

    strcpy(c,s.c_str());

3.char * 转 const char*

    char* c = "abc";

    const char * c_s = c;

4.string 转const char*

    string s = "abc";

    const char* c_s = s.c_str();

5.char * 转string

    char *c = "abc";

    string s(c);

6.const char* 转 string

     const char * c_s = "abc";

     string s(c_s);