Concatenate Strings in C++

Concatenating two std::string objects in C++ is straightforward and can be done using the + operator or the append() method. Here’s how you can do it:

Using the + Operator

The simplest way to concatenate two strings is by using the + operator. This creates a new string by combining the contents of two strings.

1#include <iostream>
2#include <string>
3
4int main() {
5  std::string FirstName{"John"};
6  std::string LastName{"Doe"};
7  std::string FullName
8    = FirstName + " " + LastName;  
9
10  std::cout << FullName;
11}

1John Doe

Using the append() Method

Alternatively, you can use the append() method to concatenate strings. This method modifies the original string.

1#include <iostream>
2#include <string>
3
4int main() {
5  std::string Greeting{"Hello"};
6  std::string Name{"Alice"};
7
8  Greeting.append(" ").append(Name);  
9
10  std::cout << Greeting;
11}

1Hello Alice

Using += Operator

You can also use the += operator to append a string to an existing string:

1#include <iostream>
2#include <string>
3
4int main(){
5  std::string Greeting{"Hello"};
6  std::string Name{"Alice"};
7
8  Greeting += " " + Name;
9
10  std::cout << Greeting;
11}

1Hello Alice

Considerations

• Performance: The + operator creates a new string, which can be less efficient than append() if used repeatedly in a loop.
• Readability: Using + can make the code more readable and concise.

By using these methods, you can easily concatenate std::string objects in C++, depending on your specific needs and performance considerations.