std::string::append() in C++

The string::append() in C++ is used append the characters or the string at the end of the string. It is the member function of std::string class .

The string::append() function can be used to do the following append operations:

Append a Whole String

The string::append() method can be used to append the whole string at the end of the given string. We just need to pass the string to be appended as the parameter to string::append () function.

Syntax

str1.append(str2);

Parameter

• str1: String in which we have to append the string.
• str2: String which we have to append at the end.

Return value

• It will return the original string after appending the string.

Example

// C++ Program to show how to append the string
// at the end of the given string
#include <bits/stdc++.h>
using namespace std;

int main() {
    string str1("Hello World! ");
    string str2("GeeksforGeeks");

    // Append the str2 in to str1
    str1.append(str2);

    cout << str1 << endl;

    return 0;
}

Hello World! GeeksforGeeks

Append a Part of the String

The string::append() method can also be used to append the substring starting from the particular position till the given number of characters.

Syntax

str1.append(str2, pos, num);

Parameter

• pos: Starting position of the substring from which we have to append.
• num: Number of characters which we have to append.

Return value

• It will return the original string after appending the string.

Example

// C++ Program for appending the substring at
// the end of the string
#include <bits/stdc++.h>
using namespace std;

int main() {
  	string str1("Hello World! ");
    string str2("GeeksforGeeks ");
    

    // Appends 5 characters from 0th index of
    // str2 to str1
    str1.append(str2, 0, 5);
  
    cout << str1;

    return 0;
}

Hello World! Geeks

Append a Character Multiple Times

The string::append() method is used to append the multiple characters at the end of the string.

Syntax

str.append(num, c);

Parameter

• str: Name of the string in which we have to append the characters.
• c: Character which we have to append multiple times.
• num: Number of times up to which characters will append.

Return value

• It will return the original string after appending the string.

Example

// C++ Program for appending multiple copies
// of the same character.
#include <bits/stdc++.h>
using namespace std;

int main() {
    string str("Hello Geeks");

    // Appends 5 occurrences of '!'
    // to str
    str.append(5, '!');
    cout << str;
  
    return 0;
}

Hello Geeks!!!!!

Append Characters from a Given Range

The string::append() method can also be used to append the characters from the given range at the end of the string.

Syntax

str.append(first, last);

Parameter

• first: Iterator pointing to the first position from which we have to append.
• last: Iterator pointing to the element just after the last element up to which we have to append.

Return value

• It will return the original string after appending the string.

Example

// C++ Program for appending the
// string in the given range
#include <bits/stdc++.h>
using namespace std;

int main() {
    string str1("Hello World! ");
    string str2("GeeksforGeeks");

    // Appends all characters from
    // str2.begin()+5, str2.end() to str1
    str1.append(str2.begin() + 5, str2.end());

    cout << str1;
    return 0;
}

Hello World! forGeeks