How to concatenate two strings in C++

In the C++ programming language, the concatenation of two or even more strings is covered in this section. The term "string concatenation" refers to a collection of characters that join two or more strings to form a single concatenated string. The second string is attached to the end of the first string to form a single string when concatenating the strings.

What is a String in C++?

In C++, a string is an object that represents a set (or collection) of various characters. Strings in C++ are members of the standard string class (std::string). A string's characters are kept as a collection of bytes in the shared storage regions by the string class. Strings are most commonly applied in the programmes that require text manipulation. In the C++ programming language, we might execute a number of different operations on the strings. For example, we can use reversing, concatenating, or even sending a function as an argument.

Syntax :

The syntax for the creation of a string in C++ is very much sorted and clear. So knowing more about strings, we will now discover various ways to define a string.

• The best and most easy approach to define a string is to use the string keyword. The string keyword should be used wherever possible because it is simple to write and comprehend. Before the string keyword is used, we should first include the standard string class into our application.

string strng_name = "It’s a C++ string";

• Then there are the strings in the C style. The following are the several methods for creating C style strings:

char strng_name[8] = {'C', 'o', 'm', 'p', 'u', ‘t', ‘e’, ‘r’, ‘\0'};
//or
char strng_name[8] = “Computer;

• It is not required to utilise all the space given to a character array (string):

char strng_name[50] = "Computer";

Concatenation of Strings :

Merging two or more strings to generate a resulting string is termed the concatenation of strings. If we desire to concatenate two or more strings, C++ offers us the functionality to achieve the same.

Example :

we have two strings, 'Comp' and 'uter', and we just want to concatenate to form a single string like Comp + uter = Computer.

In C++, there are three major techniques for concatenating the strings. They are :

1.Using strcat() method

To utilise the strcat() method, we have to include the cstring, a header file into our application. The strcat() method uses two character arrays as input. It concatenates the second array to the ending of the first array.

Syntax :

strcat(char_arr1, char_arr2);

It is vital to remember that the strcat() method only takes character arrays as its inputs. We can’t utilise string objects in the method.

Example :

#include <iostream>
#include <cstring>
using namespace std;


int main() {
  char strng1[] = "Strings ";
  char strng2[] = "Concatenated.";


  strcat(strng1, strng2);


  cout << strng1 << endl;


  return 0;
}

Output :

Strings Concatenated.

Explanation :

In the above example, we used the strcat() method to concatenate the 2 given strings strng1 and strng2. Then we printed the strng1 and got the output as concatenated string.

2.Using append() method :

The append() method adds the first string to the second string. The parameters of type string are utilised with this method.

Syntax :

strng1.append(strng2);

Example :

#include <iostream>
using namespace std;


int main() {
  string strng1 = "Strings ";
  string strng2 = "Concatenated.";


  strng1.append(strng2);


  cout << strng1 << endl;


  return 0;
}

Output :

Strings Concatenated.

Explanation :

In the above example, we used the append() method to concatenate the two give strings strng1 and strng2. By using the append() method, we added the strng1 to the strng2 and got the output as a concatenated string.

3.Using '+' operator :

This is the easiest approach to concatenate strings. The + operator combines multiple strings together and then returns the concatenated string.

Syntax :

strng1 + strng2;

Example :

#include <iostream>
using namespace std;


int main() {
  string strng1 = "Strings ";
  string strng2 = "Concatenated.";


  strng1 = strng1 + strng2;


  cout << strng1 << endl;


  return 0;
}

Output :

Strings Concatenated.

Explanation :

In the above example, we used the “+” operator to concatenate the two given strings strng1 and strng2. The added value of the two strings was stored in the string strng1 itself. Finally, the strng1 was printed to get the concatenated string.

Whether to use '+' operator or append() is solely the choice of the coder . The append() method is significantly quicker than + operation. In those applications where the strings are short, even substituting a ‘+’ operator with the append() method has no major impact on the programme’s performance. The strcat() method, in contrast, definitely have some of the potential performance difficulties because of its temporal complexity and the number of times it is called in the application. In order to give a crisp overview, the append() method or the ‘+’ operator are one of the best options anyday.

Conclusion

In C++, we can concatenate strings using one of three methods:

• the strcat() method
• the append() method, or
• the '+' operator.