C++11がもたらす新しい数値と文字列変換関数

数値回転文字列:

std::string str;  
int a = std::stoi(str); 
float b = std::stof(str);
double b = std::stod(str);

文字列の回転数:

string to_string (int val);
string to_string (long val);
string to_string (long long val);
string to_string (unsigned val);
string to_string (unsigned long val);
string to_string (unsigned long long val);
string to_string (float val);
string to_string (double val);
string to_string (long double val)