#include <string>
  string();
  string( const string& s );
  string( size_type length, const char& ch );
  string( const char* str );
  string( const char* str, size_type length );
  string( const string& str, size_type index, size_type length );
  string( input_iterator start, input_iterator end );
  ~string();

The string constructors create a new string containing:

• nothing; an empty string,
• a copy of the given string s,
• length copies of ch,
• a duplicate of str (optionally up to length characters long),
• a substring of str starting at index and length characters long
• a string of characters denoted by the start and end iterators

For example,

   string str1( 5, 'c' );
   string str2( "Now is the time..." );
   string str3( str2, 11, 4 );
   cout << str1 << endl;
   cout << str2 << endl;
   cout << str3 << endl;            

displays

   ccccc
   Now is the time...
   time         

The string constructors usually run in linear time, except the empty constructor, which runs in constant time.