.find() in c++ code example

Example 1: find function in c++

// find function for strings
// my linkedin : https://www.linkedin.com/in/vaalarivan-prasanna-3a07bb203/
str = "Ilayathapathy";
subStr = "thalapathy";
cout << str.find(subStr, 1);  // prints 5 (first occurrence of substring \n
// starting at index 1

Example 2: c++ string contains

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

Example 3: std string find character c++

// string::find
#include <iostream>       // std::cout
#include <string>         // std::string

int main ()
{
  std::string str ("There are two needles in this haystack with needles.");
  std::string str2 ("needle");

  // different member versions of find in the same order as above:
  std::size_t found = str.find(str2);
  if (found!=std::string::npos)
    std::cout << "first 'needle' found at: " << found << '\n';

  found=str.find("needles are small",found+1,6);
  if (found!=std::string::npos)
    std::cout << "second 'needle' found at: " << found << '\n';

  found=str.find("haystack");
  if (found!=std::string::npos)
    std::cout << "'haystack' also found at: " << found << '\n';

  found=str.find('.');
  if (found!=std::string::npos)
    std::cout << "Period found at: " << found << '\n';

  // let's replace the first needle:
  str.replace(str.find(str2),str2.length(),"preposition");
  std::cout << str << '\n';

  return 0;
}