• you should use cin and cout

      int a;
  cin >> a;
  cout << "your input : " << a << endl;

and your output will be your input : 23

also we can do

	string input;
	getline(cin, input);

and after, we can change it to other data types by stoi or stod .. or whatever.

  • compiling

      $ g++ hello.cpp
  $ ./a.out

  • string

string can be initiailized as a charcter array or a string class

	string str1 = {'a', 'b', 'c', 'd', '\0'};
	string str2 = "abcd";		
	
	string str3("alsoCanDoThis");

we can also use str1.size() and str2.empty() to check their size and whether if they’re empty.

	string input;
	getline(cin, input);
	string uid = input.assign(input);
	string uidFirstFive = input.assgin(input, 0, 5);
	
	uid.insert(0, "idIs : "); // will insert the string to 0 position 
	uid.erase(5, 4); // erase 4 characters from position 5
	uid.replace(3, 4, "abc"); // will erase the 4 characters from position 3 and replace it with abc
	uid.find("jinmo", 0); // will get the index of the first occurence of the string, and 0 is where I want to start searching

	string str("abc is abc but not dmc");
	string str2("abc");
	
	size_t found = str.find(str2);
	if (found != std::string::npos) { // npos is the largest value of integer. often used as until the end of the string
		std::cout >>  "first abc found at : " << found << '\n' << endl;
	}

str1.compare(str); will return 0 because the’re the same. If str1 is bigger (if starts with b or else) it will return 1, else it will return -1;