cppreference.com > C++ Strings > find
find
Syntax:
  #include <string>
  size_type find( const string& str, size_type index );
  size_type find( const char* str, size_type index );
  size_type find( const char* str, size_type index, size_type length );
  size_type find( char ch, size_type index );

The function find() either:

For example:

   string str1( "Alpha Beta Gamma Delta" );
   unsigned int loc = str1.find( "Omega", 0 );
   if( loc != string::npos )
     cout << "Found Omega at " << loc << endl;
   else
     cout << "Didn't find Omega" << endl;