How to Replace a Substring in a String using Regular Expression in C++ - Step by Step Examples

How to Replace a Substring in a String using Regular Expression in C++ ?

Answer

To replace all occurrences of a substring in a string using regular expression in C++, you can use the std::regex_replace function from the header.

✐ Examples

1 Replace Substring "Hello" with "Hi"

In this example,

We include the header.
We define a regular expression pattern matching "Hello".
We use the std::regex_replace function to replace all occurrences of the pattern with "Hi".
Finally, we print the modified string.

C++ Program

#include <iostream>
#include <regex>

int main() {
	std::string str = "Hello World Hello";
	std::regex pattern("Hello");
	std::string newStr = std::regex_replace(str, pattern, "Hi");
	std::cout << newStr << std::endl;
	return 0;
}

Output

Hi World Hi

2 Replace Digits with 'Y'

In this example,

We include the header.
We define a regular expression pattern matching digits (\d).
We use the std::regex_replace function to replace all occurrences of the pattern with 'Y'.
Finally, we print the modified string.

C++ Program

#include <iostream>
#include <regex>

int main() {
	std::string str = "Hello123World789";
	std::regex pattern("\\d");
	std::string newStr = std::regex_replace(str, pattern, "Y");
	std::cout << newStr << std::endl;
	return 0;
}

Output

HelloYYYWorldYYY

Summary

In this tutorial, we learned How to Replace a Substring in a String using Regular Expression in C++ language with well detailed examples.

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How to Replace a Substring in a String using Regular Expression in C++ - Step by Step Examples

How to Replace a Substring in a String using Regular Expression in C++ ?

Answer

✐ Examples

1 Replace Substring "Hello" with "Hi"

C++ Program

Output

2 Replace Digits with 'Y'

C++ Program

Output

Summary

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