how to use string find in c++ code example

Example 1: string .find in c++

std::string t = "Banana Republic";
std::string s = "nana";

std::string::size_type i = t.find(s);

if (i != std::string::npos)
   t.erase(i, s.length());

Example 2: c++ find string in string

#include <iostream>
#include <string>
#include <algorithm>
#include <functional>

int main()
{
    std::string in = "Lorem ipsum dolor sit amet, consectetur adipiscing elit,"
                     " sed do eiusmod tempor incididunt ut labore et dolore magna aliqua";
    std::string needle = "pisci";
    auto it = std::search(in.begin(), in.end(),
                   std::boyer_moore_searcher(
                       needle.begin(), needle.end()));
    if(it != in.end())
        std::cout << "The string " << needle << " found at offset "
                  << it - in.begin() << '\n';
    else
        std::cout << "The string " << needle << " not found\n";
}