char、string、int的相互转化

1、string 转 const char*

//> string -> const char*
string str = "example";
const char* p = str.data();  //> 1st approach
const char* p = str.c_str(); //> 2nd approach

2、char* 转 string

//> char* -> string
char* p = "example";
string str = p;

3、int 转 string

//> int -> string
int t = 100;
string str;
stringstream ss; //> stringstream class is used to type transform 
ss.clear();      //> clear object to overloaded a new string type data
ss << t;         //> input int to object
ss >> str;       //> output string from object