Check out example codes for "append string c++". It will help you in understanding the concepts better.

Code Example 1

// appending to string
#include <iostream>
#include <string>

int main ()
{
  // easy way
  std::string str = "Hello";
  std::string str2 = " World";
  std::cout << str + str2 << std::endl;
  return 0;
}

Code Example 2

#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();
}

Code Example 3

// appending to string
#include <iostream>
#include <string>

int main ()
{
  std::string str;
  std::string str2="Writing ";
  std::string str3="print 10 and then 5 more";

  // used in the same order as described above:
  str.append(str2);                       // "Writing "
  str.append(str3,6,3);                   // "10 "
  str.append("dots are cool",5);          // "dots "
  str.append("here: ");                   // "here: "
  str.append(10u,'.');                    // ".........."
  str.append(str3.begin()+8,str3.end());  // " and then 5 more"
  str.append<int>(5,0x2E);                // "....."

  std::cout << str << '\n';
  return 0;
}

Code Example 4

// string::operator+=
#include <iostream>
#include <string>

int main ()
{
  std::string name ("John");
  std::string family ("Smith");
  name += " K. ";         // c-string
  name += family;         // string
  name += '\n';           // character

  std::cout << name;
  return 0;
}

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