how to concat in c++ code example

Example 1: concat string in c++

#include <iostream>
#include <sstream>

int main() {
  std::string value = "Hello, " + "world!";
  std::cout << value << std::endl;

  //Or you can use ostringstream and use integers too
  //For example:

  std::ostringstream ss;
  ss << "This is an integer" << 104;
  std::cout << ss.str() << std::endl;
}

Example 2: appending string in c++

#include<iostream>
#include <string>
int main() {
	//"Ever thing inside these double quotes becomes const char array"
//	std::string namee = "Caleb" +"Hello";//This will give error because adding const char array to const char array 
	std::string namee = "Caleb";
	namee += " Hello";//This will work because adding a ptr to a actual string
	std::cout << namee << std::endl;// output=>Caleb Hello
//You can also use the below
	std::string namee2 = std::string("Caleb")+" Hello";// This will work because constructor will convert const char array  to string, adding a ptr to string
	std::cout << namee2 << std::endl;// output=>Caleb Hello
	std::cin.get();
}