C++/String/string search

string search with custom comparison function

<source lang="cpp">

/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

1. include <string>
2. include <iostream>
3. include <algorithm>

using namespace std; bool nocase_compare (char c1, char c2) {

   return toupper(c1) == toupper(c2);

} int main() {

   string s1("This is a string");
   string s2("STRING");
   
   // compare case insensitive
   if (s1.size() == s2.size() &&        // ensure same sizes
       equal (s1.begin(),s1.end(),      // first source string
              s2.begin(),               // second source string
              nocase_compare)) {        // comparison criterion
       cout << "the strings are equal" << endl;
   }
   else {
       cout << "the strings are not equal" << endl;
   }
   // search case insensitive
   string::iterator pos;
   pos = search (s1.begin(),s1.end(),   // source string in which to search
                 s2.begin(),s2.end(),   // substring to search
                 nocase_compare);       // comparison criterion
   if (pos == s1.end()) {
       cout << "s2 is not a substring of s1" << endl;
   }
   else {
       cout << """ << s2 << "\" is a substring of \""
            << s1 << "\" (at index " << pos - s1.begin() << ")"
            << endl;
   }

} /* the strings are not equal "STRING" is a substring of "This is a string" (at index 10)

*/        
   
 </source>