1. string转const char*

string s ="abc";

const char* c_s = s.c_str();

2. const char*转string

const char* c_s ="abc";

string s(c_s);

3. string转char*

string s ="abc";

char* c;

const int len = s.length();

c =new char[len+1];

strcpy(c,s.c_str());

4. char*转string

char* c ="abc";

string s(c);

5. const char*转char*

const char* cpc ="abc";

char* pc =new char[100];//足够长

strcpy(pc,cpc);

6. const char*转int

const char* cpc ="123";

int i=atoi(cpc);

7. string转int

string s ="abc";

int i=stoi(s);

8. int转string

int i=123;

string s=to_string(i);

9. char转int

char c='6';

int i=c-'0';