how to replace character from string c++ code example

Example 1: c++ replace character in string

#include <algorithm>
#include <string>

void some_func() {
  std::string s = "example string";
  std::replace( s.begin(), s.end(), 'x', 'y'); // replace all 'x' to 'y'
}

Example 2: c++ replace character in string

#include <string>
#include <regex>

using namespace std;

string test = "abc def abc def"; // The string to replace

// You need to write your part to replace inside the regex(), and write what is the replacement after
test = regex_replace(test, regex("abc"), "Ziv"); // The replacement.

Example 3: replace a char in string c++ at a specific index

string a = "lol";
	a[2] = 'j';
	cout << a;
//output: loj