std:🧵:replace() in C++ (original) (raw)

The std:🧵:replace() function in C++ is used to replace characters or substrings inside a string. It is a member function of the std::string class and provides multiple overloads for replacing text using indexes or iterators.

It can replace characters, substrings, or ranges of characters.
It supports replacement using indexes as well as iterators. C++ `

#include #include using namespace std;

int main() {

string str = "Hello World";

str.replace(6, 5, "C++");

cout << str;

return 0;

}

**Explanation:

Replacement starts from index 6.
5 characters (World) are replaced with "C++".

Common Syntax of string::replace()

Syntax	Description
str.replace(pos, count, n, ch)	Replaces count characters starting from pos with n copies of character ch.
str.replace(pos, count, str2)	Replaces characters with another string.
str.replace(pos1, count, str2, pos2, len)	Replaces characters with a substring of another string.
str.replace(first, last, n, ch)	Replaces iterator range with repeated characters.
str.replace(first, last, str2)	Replaces iterator range with another string.
str.replace(first, last, str2_first, str2_last)	Replaces iterator range with another iterator range.

Replace Using Indexes

n index-based replacement, positions are specified using integer indexes.

Replace with Repeated Character

The string::replace() method can be used to replace the multiple characters with single repeated character.

**Syntax

str1.**replace(pos, n, m, c)

**Parameters

**str1: String in which we have to replace the multiple characters.
**pos: Index to the position in str1 where we have to start replacing the characters.
**n: Number of characters which we have to replace.
**m: Number of times we have to repeat the single character.
**c: Character by which we have to replace.

**Return Value: It returns the original string after replacing the multiple characters with single repeated character.

C++ `

#include #include using namespace std;

int main() { string str = "Hey World";

// Replace first 3 characters with '!!!'
str.replace(0, 3, 3, '!');

cout << str;

}

Replace with Another String

**Syntax

str1.**replace(pos, n, str2)

**Parameters

**str1: String in which we have to replace.
**pos: Index to the position in str1 where we have to start replacing the characters.
**n: Number of characters which we have to replace.
**str2: String by which we have to replace the characters.

**Return Value: It returns the original string after replacing the multiple characters by another string.

C++ `

#include #include using namespace std;

int main() { string str1 = "Hey World"; string str2 = "Hello";

// Replace first 3 characters with str2
str1.replace(0, 3, str2);

cout << str1;

}

Replace with Substring

The **string::replace() method can also be used to replace the multiple characters with a part of the given string.

**Syntax

str1.**replace(pos1, n, str2, pos2,m)

**Parameters

**str1: The string in which we have to replace.
**pos1: Index to the position in str1 where we have to start replacing the characters.
**n: Number of characters which we have to replace.
**str2: String by which we have to replace the characters.
**pos2: Starting index of substring which we have to replace with multiple characters.
**m: Numbers of the character in the substring by which we have to replace.

**Return Value: It returns the original string after replacing the multiple characters by another substring.

C++ `

#include #include using namespace std;

int main() { string str1 = "Hello Geeks"; string str2 = "Hey World";

// Replace "Geeks" with substring "World"
str1.replace(6, 5, str2, 4, 5);

cout << str1;

}

Replace Using Iterator

Replace Iterator Range with Repeated Character

The **string::replace() method can be used to replace the multiple characters with a single repeated character.

**Syntax

str1.**replace(first, last, n, c);

**Parameters

**str1: The string in which we have to replace the multiple characters.
**first: Iterator pointing to the starting position of str1 from where we have to replace the multiple characters.
**last: Iterator pointing to the position just after the last element up to which we have to replace.
**n: Number of single repeated character by which we have to replace.
**c: Character by which we have to replace.

**Return Value: It return the original string after replacing the multiple characters with single repeated character.

C++ `

#include #include using namespace std;

int main() { string str = "Hey World";

auto first = str.begin();
auto last = str.begin() + 3;

// Replace first 3 characters with '!!!'
str.replace(first, last, 3, '!');

cout << str;

}

Replace with Another String

The **string::replace() method can also be used to replace the multiple characters with a string.

**Syntax

str1.**replace(first, last, str2)

**Parameters

**str1: The string in which we have to replace the multiple characters.
**first: Iterator pointing to the starting position of str1 from where we have to replace the multiple characters.
**last: Iterator pointing to the position just after the last element up to which we have to replace.
**str2: String by which we have to replace the characters.

**Return Value: It return the original string after replacing the multiple characters by another string.

C++ `

#include #include using namespace std;

int main() { string str1 = "Hey World"; string str2 = "Hello World";

str1.replace(str1.begin(), str1.end(), str2);

cout << str1;

}

Replace with Substring (Iterator Range)

The **string::replace() method can also be used to replace the multiple characters with a substring.

**Syntax

str1.**replace(first, last, str2_first, str2_last)

**Parameters

**str1: The string in which we have to replace the multiple characters.
**first: Iterator pointing to the starting position of str1 from where we have to replace.
**last: Iterator pointing to the position just after the last element up to which we have to replace.
**str2_first: Iterator pointing to the starting position of substring by which we have to replace.
**str2_last: Iterator pointing to the position just after the last element of the substring.

**Return Value: It returns the original string after replacing the multiple characters by another substring.

C++ `

#include #include using namespace std;

int main() { string str1 = "Hello Geeks"; string str2 = "Hey World";

auto first = str1.begin() + 6;
auto last = str1.end();

auto str2_first = str2.begin() + 4;
auto str2_last = str2.end();

str1.replace(first, last, str2_first, str2_last);

cout << str1;

}