what data type can be used for entering string in c++.after declaration i am going to use cin

Answer 1

you can use traditional char array, which the characters is limited to its size
char str[10];

or std::string, std::string itself is a class representing a sequences of characters
std::string str;

//example
std::string input;
std::cin>>input;
//or
char input[10]; // can hold 9 characters
std::cin>>input

Answer 2

what is tge syntax? pls give me a program as ecample