string find in c 2b 2b

1if (string1.find(string2) != std::string::npos) {
2    std::cout << "found!" << '\n';
3}

1// string::find
2#include <iostream>       // std::cout
3#include <string>         // std::string
4
5int main ()
6{
7  std::string str ("There are two needles in this haystack with needles.");
8  std::string str2 ("needle");
9
10  // different member versions of find in the same order as above:
11  std::size_t found = str.find(str2);
12  if (found!=std::string::npos)
13    std::cout << "first 'needle' found at: " << found << '\n';
14
15  found=str.find("needles are small",found+1,6);
16  if (found!=std::string::npos)
17    std::cout << "second 'needle' found at: " << found << '\n';
18
19  found=str.find("haystack");
20  if (found!=std::string::npos)
21    std::cout << "'haystack' also found at: " << found << '\n';
22
23  found=str.find('.');
24  if (found!=std::string::npos)
25    std::cout << "Period found at: " << found << '\n';
26
27  // let's replace the first needle:
28  str.replace(str.find(str2),str2.length(),"preposition");
29  std::cout << str << '\n';
30
31  return 0;
32}

1const char* c = "Word";
2string str = "WhereIsMyWordThatINeed";
3cout << "the word is at index " << str.find(c);
4//this will print "the word is at index 9"

1#include <iostream>
2#include <string>
3#include <algorithm>
4#include <functional>
5
6int main()
7{
8    std::string in = "Lorem ipsum dolor sit amet, consectetur adipiscing elit,"
9                     " sed do eiusmod tempor incididunt ut labore et dolore magna aliqua";
10    std::string needle = "pisci";
11    auto it = std::search(in.begin(), in.end(),
12                   std::boyer_moore_searcher(
13                       needle.begin(), needle.end()));
14    if(it != in.end())
15        std::cout << "The string " << needle << " found at offset "
16                  << it - in.begin() << '\n';
17    else
18        std::cout << "The string " << needle << " not found\n";
19}

1If not found then returns npos or -1 in int